WO 2006/088833 PCT/US2006/005111
TITLE
INTERLEUKIN-17F ANTIBODIES AND OTHER IL-17F SIGNALING
ANTAGONISTS AND USES THEREFOR
Related Applications
[0001] This application claims priority to U.S. Provisional Patent Application
No. 60/653,260, filed February 14,2005; and U.S. Provisional Patent Application
No. 60/667,492, filed April 1, 2005, both of which are hereby incorporated by
reference herein in their entireties.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] This invention relates to antibodies, e.g., intact antibodies and antigen-
binding fragments thereof, and other DL-17F signaling antagonists, e.g., soluble
IL-17F receptor(s), that interfere with interleukin-17F (TL-17F) signaling, in
particular, human IL-17F, and their uses in regulating IL-17F-associated
activities. The antibodies and related IL-17F molecules disclosed herein are
useful in diagnosing, prognosing, monitoring, preventing, and/or treating IL-17F-

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associated disorders, e.g., inflammatory disorders (e.g., autoimmune diseases
(e.g., arthritis (including rheumatoid arthritis), psoriasis, systemic lupus
erythematosus (SLE), multiple sclerosis), respiratory diseases (e.g., COPD, cystic
fibrosis, asthma, allergy), transplant rejection (including solid organ transplant
rejection), and inflammatory bowel diseases or disorders (IBDs, e.g., ulcerative
colitis, Crolm's disease)).
Related Background Art
[0003] Cytokines are secreted soluble proteins with pleiotropic activities
involved in immune and inflammatory responses, e.g., cytokines may cause
differentiation, recruitment, or other physiological responses, e.g., secretion of
proteins characteristic of inflammation, by target cells. Cytokines bind to
specific cell surface receptors, triggering signal transduction pathways that lead
to cell activation, proliferation, and differentiation. One such cytokine,
interleukin-17 (IL-17), originally named CTLA-8, was isolated and cloned from
rnurine hybridornas and shown to have hornology to open reading frame 13 of the
T lymphotropic Herpesvirus saimiri (Rouvier et al. (1993) J. Immunol. 150:5445-
56; Yao et al. (1996) Gene 168:223-25; Golstein et al., published International
Patent Application No. WO95/01826). Since then, five related cytokines that
share 20-50% homology to IL-17 have been identified (see Moseley et al. (2003)
Cytokine & Growth Factor ReviewsU: 155-74). To indicate IL-17 as the
founding member of the IL-17 cytokine family, it has been designated IL-17A
(Moseley, supra); the other members have been designated IL-17B, IL-17C,
IL-17D, IL-17E, and IL-17F. IL-17 cytokine family members share conserved
cysteine residues. Of interest are IL-17A and particularly IL-17F, which share
50% identity; both, cytokines are induced by IL-23, coexpressed by T cells, and
considered potential targets for T cell-mediated autoimmune diseases. Similar to
IL-17A, the conserved cysteine residues in IL-17F exhibit features of a classic
cysteine knot motif found in bone morphogenetic proteins (BMPs), transforming
growth factor-beta (TGF-p), nerve growth factor (NGF) and platelet-derived
factor BB (PDGF-BB) (Hymowitz et al. (2001) EMBO J. 20:5332-41; McDonald
et al. (1993) Cell 73:421-24).

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[0004] EL-17F is a 17kD secreted protein that was cloned from an activated
human PBMC library (SST) (U.S. Patent Nos. 6,043,344 and 6,074,849). It
forms a 30-35KD disulfide-linked homodimer (Hymowitz, supra) and, similar to
IL-17A, is expressed primarily by activated T cells (Moseley, supra). However,
expression of IL-17F by activated monocytes, activated basophils and mast cells
has also been shown (Kawaguchi et al. (2002) J. Immunol. 167:4430-35). IL-17F
induces the expression of many cytokines and chemokines by macrophages,
endothelial cells, epithelial cells, and fibroblasts (Moseley, supra).
[0005] IL-17F plays a role in inflammatory responses, in part, by inducing the
production of inflammatory cytokines and neutrophilia. It is associated with the
development of several autoimmune diseases, e.g., arthritis (including
rheumatoid and Lyme arthritis), systemic lupus erythematosus (SLE), and asthma
(Bettelli and Kuchroo (2005) /. Exp.Med. 201:169-71). For example, it has
recently been shown that EL-23 is essential for the expansion of a T cell
population which is characterized by, inter alia, production of IL-17F, that
passive transfer of this T cell population is essential for the establishment of
organ-specific inflammation associated with central nervous system
autoimmunity (Langrish et al. (2005) /. Exp. Med. 201:233-40), and that EL-17-
deficient mice are resistant to experimental autoimmune encephalomyelitis
(EAE; an animal model for multiple sclerosis) (Nakae et al. (2003) /. Immunol.
171:6173-77). IL-17F is unique among known inflammatory cytokines in that it
increases proteoglycan breakdown and decreases proteoglycan synthesis by
articular cartilage (Hymowitz, supra). Additionally, increased expression of
IL-17F has been demonstrated in bronchoalveolar lavages (BALs) taken from
patients suffering with asthma after allergen challenge compared to BALs taken
from these patients as controls (Kawaguchi, supra). Also, IL-17F mRNA
expression is increased in patients with ulcerative colitis and Crohn's disease
(Gurney et ai. (2003) GTCBIO Conf: Cytokines and Beyond). These observations
suggest that blockade of IL-17F signaling will reduce proinflammatory cytokine
production and decrease bone erosion. Consequently, the IL-i7F signaling
pathway is an attractive target for treating and/or preventing rnflammatory
diseases, e.g., in which recruited neutrophils are critical mediators of tissue

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injury, e.g., during the development of autoimmune diseases (e.g., arthritis
(including rheumatoid arthritis), psoriasis, systemic lupus erythematosus,
multiple sclerosis), respiratory diseases (e.g., COPD, cystic fibrosis, asthma,
allergy), transplant rejection (including solid organ transplant rejection), and
inflammatory bowel disorders or diseases (TBDs, e.g., ulcerative colitis, Crohn's
disease).
[0006] Currently, not much is known about the receptors for members of the
IL-17 family. It has been shown that IL-17R, the receptor for IL-17A, is
expressed in all tissues examined to date, and that binding of IL-17R by IL-17A
generally results in the induction of proinflammatory cytokines through
activation of NF-KB (Moseley, supra). Four additional receptors that share
partial sequence homology to IL-17R have been identified: 1) IL-17RH1 (also
called IL-17RB), 2) IL-17-receptor like protein (also called IL-17RL or
IL-17RC), 3) IL-17RD (also called SEF or IL-17RLM), and 4) EL-17RE
(Moseley, supra). Of these four additional receptors, only IL-17RH1 has been
shown to bind to IL-17 cytokices, namely IL-17B and IL-17E; however, the
function of IL-17B and IL-17E binding to IL-17RH1 has not been shown (Shi et
al. (2000) /. Biol Chem. 275:19167-76; Lee et al. (2001) J. Biol. Chem.
276:1660-64). To date, the receptor(s) for EL-17F has not been reported. Thus,
IL-17F signaling has not been able to be targeted for the prevention and/or
treatment of diseases, although it may play an important role in the homeostasis
of tissues (e.g., joint tissues) and the progression of various diseases (e.g.,
arthritis, asthma, allergy, COPD, cystic fibrosis, ulcerative colitis, Crohn's
disease, etc.). The present invention solves this problem by identifying and
targeting key players involved in the signal transduction pathway of IL-17F
protein.
SUMMARY OF THE INVENTION
[0007] An object of the invention is to identify components of the IL-17F
signaling pathway, e.g., IL-17F and its receptor, and to target these components
in methods of treating disorders related to IL-17F signaling. Such IL-17F-
associated disorders and disorders related to increased IL-17F signaling include,

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but are not limited to, inflammatory disorders, e.g., autoimmune diseases (e.g.,
arthritis (including rheumatoid arthritis), psoriasis, systemic lupus erythematosus,
multiple sclerosis), respiratory diseases (e.g., COPD, cystic fibrosis, asthma,
allergy), transplant rejection (including solid organ transplant rejection), and
inflammatory bowel diseases (e.g., ulcerative colitis, Crohn's disease).
[0088] As such, the research underlying the present invention provides evidence
that IL-17F mediates proteoglycan destruction and inflammatory responses
through its binding to IL-I.7R and/or JL-17RC. The determination of TL-17R and
IL-17RC as receptors for EL-17F exposes these molecules as targets for the
treatment of disorders related to IL-17F signaling.
[0009] Provided herein are EL-17F signaling antagonists, including, but not
limited to, IL-17F inhibitory polynucleotides, EL-17R inhibitory polynuclcotides,
IL-17RC inhibitory polynucleotides, soluble polypeptides comprising IL-17R or
IL-17F-bmding fragments thereof, soluble polypeptides comprising IL-17RC or
IL-17F-binding fragments thereof, inhibitory anti-IL-17F antibodies, inhibitory
anti-IL-17R antibodies, inhibitory anti-IL-17RC antibodies, and antagonistic
small molecules. Preferred examples of IL-17F signaling antagonists include
siRNAs directed to EL-17R and IL-17RC, soluble fusion proteins comprising IL-
17R and E.-17RC (or IL-17F-binding fragments thereof), and inhibitory (i.e.,
antagonistic) IL-17F antibodies. In another preferred embodiment of the
invention, an IL-17F signaling antagonist, e.g., siRNAs directed against IL-17R
or IL-17RC, soluble fusion proteins comprising IL-17R or EL-17RC (or IL-17F
binding fragments thereof), or inhibitory IL-17F antibodies, decreases IL-17F
bioactivity and/or the ability of NF-KB to activate NF-KB responsive genes.
[0010] Additionally, based on structural and sequence similarity between IL-17A
and EL-17F, the inventors hypothesized and demonstrated the formation of novel
IL-17A/EL-17F heterodiiners. In demonstrating the existence of IL-17A/IL-17F
heterodimers, the inventors are the first to demonstrate that IL-21 results in the
increased production of H-17A homodimers, IL-17F homodimers, and
IL-17A/IL-17F heterodimers, and suggest that effects associated with IL-21
binding to and activating IL-21R may be due, at least in part, to IL-17 signaling.

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The inventors are also the first to isolate IL-17A homodimers, EL-17F
homodimers and IL-17A/IL-17F heterodimers from a natural source of these
cytokines, e.g., activated T cells; Thus, the invention also provides methods of
mitigating effects associated with IL-21 binding to and activating IL-21R, e.g., by-
inhibiting IL-17A and/or IL-17F signaling. Additionally, the invention provides
natural (i.e., nonrecombinanO IL-lTAhomodiniers, IL-17F homodimers, and
IL-17A/IL-17F heterodimers, and methods of isolating and targeting the same,
e.g., in methods of treating disorders associated with increased IL-17F signaling
and/or disorders associated with IL-21 binding to and activating IL-21R.
Disclosed herein additionally are recombinant IL-17A homodimers, IL-17F
homodimers, and IL-17A/IL-17F heterodimers, and methods of isolating IL-
17A/IL-17F heterodimers (either recombinant or natural) substantially free of IL-
17A homodimers and EL-17F homodimers.
[0011] Methods that target IL-17F signaling may involve IL-17F, IL-17R and/or
IL-17RC polynucleotides (including inhibitory polynucleotides such as antisense,
siRNTA, and aptamers), polypeptides, and fragments thereof as IL-17F signaling
antagonists. Additionally, antibodies capable of inhibiting the interaction of
IL-17F protein (either as an IL-17F homodimer or as an IL-17A/IL-17F
heterodimer) with its receptor(s) may also be used.
[0012] The invention also relates to using the molecules disclosed herein in
methods of screening test compounds capable of targeting the IL-17F signaling
pathway, and diagnosing, prognosing, monitoring and/or treating disorders
related to IL-17F signaling.
[0013] In one embodiment, the present invention provides a method of screening
for test compounds capable of antagonizing IL-17F signaling comprising the
steps of: contacting a sample containing IL-17F and IL-17R with a compound;
and determining whether the interaction of IL-17F with IL-17R in the sample is
decreased relative to the interaction of EL-17F with IL-17R in a sample not
contacted with the compound, whereby such a decrease in the interaction of
IL-I7F with IL-17R in the sample contacted with the compound identifies the
compound as one that inhibits the interaction of IL-17F with IL-17R and is

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capable of antagonizing IL-17F signaling. In another embodiment, the invention
provides a similar method of screening related to IL-17RC.
[0014] In another embodiment, the invention provides a method for diagnosing a
disorder related to increased IL-17F signaling in a subject comprising the steps
of: detecting a test amount of an IL-17F signaling gene product in a sample from
the subject; and comparing the test amount with a noixnai amount of the same
IL-17F signaling gene product in a control sample, whereby a test amount
significantly above the normal amount provides a positive indication in the
diagnosis of a disorder related to increased EL-17F signaling. In another
embodiment, the disorder is selected from the group consisting of autoimmune
diseases, respiratory diseases, and inflammatory bowel diseases. In other
embodiments, the IL-17F signaling gene product is an IL-17F gene product, an
IL-17R gene product, or an IL-17RC gene product.
[0015] In another embodiment, the invention provides a method of treating a
subject at risk for, or diagnosed with, a disorder related to increased IL-17F
signaling comprising administering to the subject a therapeuiically effective
amount of an IL-17F signaling antagonist. In another embodiment, the DL-17F
signaling antagonist is selected from the group consisting of IL-I7F inhibitory
polynucleotides, IL-17R inhibitory polynucleotides, IL-17RC inhibitory
polynucleotidesi soluble polypeptides comprising IL-17R or IL-17F binding
fragments thereof, soluble polypeptides comprising IL-17RC or IL-17F binding
fragments thereof, inhibitory anti-IL-17F antibodies, inhibitory anti-IL-17R
antibodies, inhibitory IL-17RC antibodies, and antagonistic small molecules. In
some embodiments, the IL-17F signaling antagonist is an IL-17R inhibitory
polynucleotide or an IL-17RC inhibitory polynucleotide. In some further
embodiments, the inhibitory polynucleotide is an siRNA selected from the group
consisting of the nucleotide sequences set forth in SEQ ID NOs: 17-32. In some
embodiments, the IL-17F signaling antagonist is a soluble polypeptide
comprising IL-17R or IL-17F binding fragments thereof, or comprising IL-17RC
or IL-17F binding fragments thereof. In some further embodiments, the soluble
polypeptide has the amino acid sequence set forth in SEQ ID NO:34 or SEQ ID
NO:35. In some other embodiments, (1) the IL-17F inhibitory polynucleotide

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comprises the nucleotide sequence set forth in, or a nucleotide sequence
complementary to the nucleotide sequence set forth in, SEQ ID NO:1 or a
fragment of SEQ ID NO:1, or an RNA equivalent thereof, and wherein
expression of the inhibitory polynucleotide in a cell results in the decreased
expression of IL-17F; (2) the IL-17R inhibitory polynucleotide comprises the
nucleotide sequence set forth in, or a nucleotide sequence cornplenientary to the
nucleotide sequence set forth in, SEQ ID NO:5 or a fragment of SEQ ID NO:5, or
an RNA equivalent thereof, and wherein expression of the inhibitory
polynucleotide in a cell results in the decreased expression of IL-17R; and (3) the
IL-17RC inhibitory polynucleotide comprises a nucleotide sequence selected
from the group consisting of the nucleotide sequences set forth in, or a nucleotide
sequence complementary to a nucleotide sequence selected from the group
consisting of the nucleotide sequences set forth in, SEQ ID NO:7, SEQ ID NO:9,
SEQ ID NO:11, SEQ ID NO:13, and SEQ ID NO:15 or a fragment of a
nucleotide sequence selected from the group consisting of the nucleotide
sequences set forth in SEQ ID NO:7, SEQ ID NO:9, SEQ ID NO:11, SEQ ID
NO:13, and SEQ ID NO:15, or an RNA equivalent thereof, and wherein
expression of the inhibitory polynucleotide in a cell results in the decreased
expression of IL-17RC. In some embodiments, the disorder related to increased
IL-17F signaling is an inflammatory disorder. In some further embodiments, the
inflammatory disorder is selected from the group consisting of an autoimmune
disease, a respiratory disease, and an inflammatory bowel disease. In some
further embodiments, the inflammatory disorder is an autoimmune disease, and
the autoimmune disease is selected from the group consisting of arthritis
(including rheumatoid arthritis), psoriasis, systemic lupus erythematosus, and
multiple sclerosis. In some further embodiments, the inflammatory disorder is a
respiratory disease, and the respiratory disease is cystic fibrosis; or the
inflammatory disorder is an inflammatory bowel disease.
[0016] In another embodiment, the invention further comprises administering to
the subject a therapeutically effective amount of at least one additional
therapeutic agent. In another embodiment, the at least one additional therapeutic
agent is selected from the group consisting of cytokine inhibitors, growth factor

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inhibitors, immunosuppressants, anti-inflammatory agents, metabolic inhibitors,
enzyme inhibitors, cytotoxic agents, and cytostatic agents. In another
embodiment, the at least one additional therapeutic agent is selected from the
group consisting of TNF antagonists, anti-TNF agents, IL-12 antagonists, IL-15
antagonists, IL-17 antagonists, IL-18 antagonists, JL-22 antagonists, T cell-
depleting agents, B cell-depleting agents, cyclosporin, FK-506, CCI-779,
etanercept, infliximab, rituximab, adalimumab, prednisolone, azathioprine, gold,
sulphasalazine, chloroquine, hydroxychloroquine, minocycline, anakinra,
abatacept, methotrexate, leflunomide, rapamycin, rapamycin analogs, Cox-2
inhibitors, cPLA2 inhibitors, NSAJDs, p38 inhibitors, antagonists of B7.1, B7.2,
ICOSL, ICOS and/or CD28, and agonists of CTLA4.
[0017] In another embodiment, the invention provides a method of inhibiting the
ability of NF-KB to activate NF-icB-responsive promoters in a cell population or a
subject, comprising administering an IL-17F signaling antagonist to the cell
population or the subject. In another embodiment, the invention provides a
method for inhibiting an IL-17F bioactivity in a cell population or a subject, the
method comprising administering an IL-17F signaling antagonist to the cell
population or the subject. In another embodiment, the IL-17F bioactivity is
selected from the group consisting of neutrophil differentiation, neutrophil
recruitment and cytokine induction.
[0018] hi another embodiment, the invention provides a pharmaceutical
composition comprising an IL-17F signaling antagonist and a pharmaceuticaliy
acceptable carrier. In another embodiment, the invention provides a vaccine
adjuvant comprising an IL-17F signaling antagonist and an antigen selected from
the group consisting of an autoantigen, an allergen, an alloantigen, and fragments
thereof. la another embodiment, the invention provides isolated antibodies
capable of specifically binding to the ammo acid sequences related to the present
invention, including those set forth in SEQ 3D NOs:6,7,9,11,13, and 15; in
some embodiments, the antibody antagonizes IL-17F signaling.
[0019] In another embodiment, the invention provides an isolated antibody
capable of specifically binding to IL-17F protein, and further embodiments

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wherein the IL-17F protein is derived from a human or a primate; wherein the
IL-17F protein is multimeric; wherein the IL-17F protein is IL-17F homodimer or
an IL-17F heterodimer; wherein the IL-17F heterodimer is IL-17A/IL-17F; and
wherein the antibody inhibits IL-17F bioactivity.
[0020] In another embodiment, the invention provides the above-identified
methods, wherein IL-17F signaling and/or IL-i7F bioactivity is mediated by
IL-17F homodimer, an IL-17F heterodimer, or both IL-17F homodimer and an
IL-17F heterodimer, including wherein the IL-17F heterodimer is
IL47A/IL-17F.
[0021] In another embodiment, the invention provides the above-identified
pharmaceutical composition and/or the above-identified vaccine adjuvant,
wherein the IL-17F signaling antagonist antagonizes IL-17F homodimer, an IL-
17F heterodimer, or both IL-17F homodimer and an IL-17F heterodimer.
[0022] In another embodiment, the invention provides a method of inhibiting at
least one activity associated with IL-21 signaling comprising antagonizing
IL-17F signaling- In another embodiment, the invention provides a method of
inhibiting at least one activity associated with IL-23 signaling comprising
1 antagonizing IL-17F signaling. In some further embodiments, the IL-17F
signaling is mediated by IL-17F homodimer, an IL-17F heterodimer, or both IL-
17F homodimer and an IL-17F heterodimer, including wherein the IL-17F
heterodimer is IL-17A/BL-17F.
[0023] In another embodiment, the invention provides a method of purifying
natural IL-17A protein comprising: activating T cells in media; and
immunoprecipitating IL-17A protein from the media. In another embodiment,
the invention provides a method of purifying natural IL-17F protein comprising:
activating T cells in media; and immunoprecipitating IL-17F protein from the
media. In some further embodiments, such methods are provided wherein the
IL-17A protein is IL-17A homodimer, an IL-17A heterodimer, or both IL-17A
homodimer and an IL-17A heterodimer, and/or wherein the IL-17F protein is
IL-17F homodimer, an IL-17F heterodimer, or both IL-17F homodimer and an
IL-17F heterodimer; and wherein the IL-17A or IL-17F heterodimer is

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IL-17A/IL-17F. In another embodiment, the media comprises IL-21 and/or
IL-23.
[0024] In another embodiment, the invention provides an isolated IL-17F protein,
wherein the IL-17F protein is IL-17F homodimer or an IL-17F heterodimer;
wherein the IL-17F protein is isolated from a natural source; wherein the natural
source is at least one T ceil. In another embodiment, the invention provides an
isolated IL-17A protein, wherein the IL-17A protein is IL-17A homodimer or an
IL-17A heterodimer; wherein the IL-17A protein is isolated from a natural
source; wherein the natural source is at least one T cell.
[0025] In another embodiment, the invention provides a method of inhibiting at
least one activity associated with IL-17A signaling, comprising administering an
IL-17F antagonist.
[0026] In another embodiment, the invention provides a method of isolating IL-
17A/IL-17F heterodirners substantially free from IL-17A homodimers and IL-
17F homodimers, comprising: (a) expressing an IL-17A fusion protein and an IL-
17F fusion protein in host cells cultured in media, wherein the IL-17A fusion
protein comprises an IL-17A protein or fragment thereof fused to a first affinity
tag, and wherein the IL-17F fusion protein comprises an IL-17F protein or
fragment thereof fused to a second affinity tag; (b) allowing the host cells to
secrete the IL-17A fusion protein and IL-17F fusion protein into the media; (c)
placing the media over a first affinity column under nonreducing conditions such
that the IL-17A fusion protein binds to the first affinity column; (d) eluting the
bound protein from the first affinity column under nonreducing conditions; (e)
placing the eluent obtained from step (d) over a second affinity column under
nonreducing conditions such that the IL-17F fusion protein binds to the second
affinity column; and (f) eluting the bound protein from the second affinity
column under nonreducing conditions, wherein the eluent obtained from step (f)
contains both IL-17A fusion protein and IL-17F fusion protein in the form of IL-
17A/IL-17F heterodimers. In other embodiments, variations of this method are
provided. In another embodiment, the invention provides an IL-17A/EL-17F
heterodimer isolated according to these various methods.

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BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Shown in Figure 1 is NF-icB-mediated reporter transactivation (Relative
Luciferase Activity; y-axes) in (A) primary human chondrocytes or (B) primary
porcine chondrocytes cultured in various concentrations (ng/ml) of IL-17A and/or
IL-17F (x-axes).
[0028] The concentration (pg/ml; y-axis) of cytokines (IL-6, IL-8, MCP-1 or
GRO-oc; x-axis) from each of two patients (PI, P2; x-axis) in supernatant
collected from human fibroblast-like synoviocytes cultured in media (control; □)
or in the presence of 20 ng /ml IL-17F (IL-17F; ss) is shown in Figure 2.
[0029] Figure 3 demonstrates the concentration (pg/ml; y-axis) of mflammatory
cytokines (IL-6, JE (CCL2), KG; x-axis) in supernatants collected from cultures
of primary murine lung fibroblasts cultured in media (0 ng/ml rL-17F;D), or with
1 ng/ml (1), 3.3. ng/ml (ED), 10 ng/ml (ED), or 30ng/ml (■) EL-17F.
[0030] Figure 4 demonstrates binding (OD 450nm; y-axes) of increasing
concentrations of human IL-17F (left panels) or human IL-17A (right panels)
(x-axes) to (A) IL-17R-IgG (upperpanels) or (B) IL-17RC-IgG (lowerpanels) as
measured by ELISA. Also noted are EC50 values for each receptor/cytokine
interaction.
[0031] Shown in Figure 5 is the concentration of GRO-cc (pg/ml; y-axes) in
supernatant collected from human fibroblasts cultured alone (Media; -) or with
increasing concentrations (u.g/ml: x-axes) of an IL-17R-IgG fusion protein
(hl7R.Fc; ●), an IL-17RC-IgG fusion protein (hl7RH2.Fc; ■), a control IgG
protein (hlgGl; ▲), an anti-IL-17R antibody (ahIL17R; □) or control antibody
(goat IgG;A) in the presence of either (A) 0.5 ng/ml IL-17A (left panels) or (B)
20 ng/ml IL-17F (right panels).
[0032] Figure 6 demonstrates the ability of anti-human IL-17F antibodies to-
inhibit the binding of IL-17F to IL-17R (OD 450nm; y-axis) in the presence of
increasing concentrations (g/ml; x-axis) of one of the following six anti-IL-17F
antibodies: anti-EL-17F-01 (□), anti-IL-17F-02 (—), anti-IL-17F-03 (▲), anti-
IL-17F-05 (♦), anti-IL-17F-06 (●), and anti-IL-17F-07 ().

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[0033] Figure 7 demonstrates the ability of anti-human IL-17F antibodies to
inhibit the binding of IL-17F to IL-17RC (OD 450nm; y-axis) in the presence of
increasing concentrations (p,g/ml; x-axis) of each of the following six anti-IL-17F
antibodies: anti-IL-17F-01 (□), anti-IL-17F-02 (—), anti-IL-17F-03 (▲), anti-
IL-17F-05 (♦), anti-IL-17F-06 (●), and anti-IL-17F-07 ().
[0034] Shown in Figure 8 is the concentration of GRO-oc (pg/ml; y-axes) in
supernatant collected from human fibroblasts cultured in 20 ng/ml EL-17F and
increasing concentrations (jag/ml; x-axis) of (left panel) anti-IL-17F-01 (aIL-17F-
01), anti-IL-17F-02 (a!L-17F-02), or anti-IL-17F-03 (aIL-17F-03) and (right
panel) anti-IL-17F-05 (aIL-17F-05), anti-IL-17F-06 (aIL-17F-06), oranti-
IL-17F-07 (aIL-17F-07), or control mlgGl antibodies.
[0035] Shown in Figure 9 is NF-xB-mediated reporter transactivation (Relative
Luciferase Activity; y-axis) in porcine primary chondrocytes cultured in media
only (none), in 100 ng/ml IL-17A (IL-17A(100 ng/ml)), in 100 ng/mi IL-17A in
the presence of an IL-17R-IgG fusion protein (EL-17A+EL17R/FcX in 100 ng/ml
IL-17A in the presence of an anti-IL-17F antibody (IL17A+antiIL17F), inl00
ng/ml IL-17A in the presence of a control mouse IgG (IL-17A+inouseIgG), in
500 ng/ml IL-17F (IL-17F(500 ng/ml)), in 500 ng/ml IL-17F in the presence of
an IL-17R-IgG fusion protein (IL-17F+IL17R/Fc), in 500 ng/ml IL-17F in the
presence of an anti-IL-17F antibody (IL-17F+antiIL17F), or in 500 ng/ml IL-17F
in the presence of a control mouse IgG (IL-17F+mouse IgG).
[0036] The concentration (pg/ml; y-axis) of cytokines (JL-6, TL-8, or GRO-a;
x-axis) from each of two patients (P1, P2; x-axis) in supernatant collected from
human fibroblast-like synoviocytes cultured in the presence of 20 ng/ml IL-17F
(IL-17F; D), an isotype control antibody (Isotype Ab; B), Anti-IL-17F-01
antibody (S), or Anti-IL-17F-07 antibody (H) is shown in Figure 10.
[0037] Figure 11 demonstrates the detection (OD 450nm; y-axes) of IL-17A
homodimers (1L-17A/A; x-axes), IL-17F homodimers (IL-17F/F; x-axes), or
IL-17A/rL-17F heterodimers (IL-17A/F; x-axes) using ELISA formats specific
for the detection of (A) IL-17A protein (including IL-17A homodimers and

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IL-17A heterodimers) (B) IL-17F protein (including IL-17F homodimers and
IL-17F heterodirners), or (C) IL-17A/IL-17F heterodimers.
[0038] Figure 12 demonstrates the concentration (Cytokine Produced (pg/ml); y-
axes) of (A) IL-17A or (B) IL-17F in media isolated from T cells undergoing
primary activation in the presence of bead-bound anti-CD3 antibody, increasing
concentrations of anti-CD28 antibody (Anti-CD28 (ng/ml); x-axes), and in the
absence (□) or presence of IL-21 (■) orIL-23 (□).
[0039] Figure 13 demonstrates the concentration (Cytokine Produced (pg/ml); y-
axis) of IL-17A (■) or IL-17F (□) in media isolated from T cells undergoing
secondary activation under the following stimulating conditions (x-axis): IL-23
only (IL-23); IL-21 only (IL-21); bead-bound anti-CD3 antibody and anti-CD28
antibody (CD3/CD28); IL-23, bead-bound anti-CD3 antibody and anti-CD28
antibody (IL-23/CD3/CD28); IL-21, bead-bound anti-CD3 antibody and anti-
CD28 antibody (IL-2I/CD3/CD28); or media.
[0040] Figure 14 demonstrates the detection (OD 450nm; y-axes) of IL-17A
homodimers, EL-17F homodimers, or TL-17A/IL-17F heterodimers in undiluted
(neat) or diluted (1:10) media obtained from T cells subject to primary activation
(CM1) or restimulation (CM2) (x-axes) using ELISA formats specific for the
detection of (A) IL-17A protein (including IL-17A homodimers and IL-17A
heterodimers), (B) IL-17F protein (including IL-17F homodimers and IL-17F
heterodimers), or (C) IL-17A/IL-17F heterodimers.
[0041] Shown in Figure 15 is a Western blot analysis performed with polyclonal
rabbit anti-human IL-17F antibody to detect anti-human IL-17F-01
immunoprecipitates from 500 ul of conditioned media obtained from T cells
undergoing secondary activation. Controls consist of IL-17F homodimer (second
lane) prepared as described in Example 5.3, or IL-17A homodimers (fifth lane)
purchased from R&D Systems (Minneapolis, MN)- The molecular weight
standard is shown in first lane. The positions of the IL-17A and IL-17F
homodimers and IL-17F/3L-17A heterodimers are indicated by arrows.
[0042] Figure 16 is the result of a Western blot analysis performed with biotin-
conjugated goat anti-human IL-17A antibody to detect the anti-human IL-17A-02

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immunoprecipitates from 500 ul of conditioned media obtained from T cells
undergoing secondary activation. Control (lane 2) consists of IL-17F homodimer
prepared as described in Example 5.3. The molecular weight standard is shown
in lane 1. The positions of the IL-17A and IL-17F homodimers and IL-17F/IL-
17A heterodimers are indicated by arrows.
[0043] Figure 17A shows anti-IL-17F irnrnunoprccipitates (lanes 2-7) or anti-IL-
17A imrnunoprecipitates (lanes 8-10) imnmnoprobed with anti-IL-17F antibody.
Immimoprecipitates were obtained from the conditioned media (CM) of COS
cells overexpressing EL-17A (lanes 2 and 8), EL-17F (lanes 3 and 10), IL-17A and
IL-17F (lanes 4 and 9), purified EL-17A homodimer (lane 5), or purified IL-17F
homodimer (lanes 6 and 7). Controls ("A/A Purified," lane 5, and "F/F purified,"
lanes 6-7) consist of purified recombinant IL-17A and IL-17F homodimers as
described in Example 5.4. The molecular weight standard is shown in lane 1.
The positions of the IL-17A and IL-17F homodimers and IL-17F/IL-17A
heterodirner are indicated by arrows.
[0044] Figure 17B shows anti-IL-17A immunoprecipitates (lanes 2-4) or anii-IL-
17F immunoprecipitates (lanes 5-7) immunoprobed with anti-IL-17A antibody.
Iminunoprecipitates were obtained from the conditioned media (CM) of COS
cells overexpressing IL-17A (lanes 3 and 5), IL-17F (lanes 2 and 7), or IL-17A
and IL-17F (lanes 4 and 6). The molecular weight standard is shown in lane 1.
The positions of the IL-17A and IL-17F homodimers and IL-17F/IL-17A
heterodimer are indicated by arrows.
[0045] Figure 18 is a diagram showing a method of purifying recombinant JL-
17F/IL-17A heterodimers substantially free from IL-17A and IL-17F
homodimers. The method employs IL-17A and IL-17F with two different
affinity tags, and uses two separate and sequential affinity columns to isolate IL-
17F/IL-17A heterodimers.
[0046] Figure 19A shows that recombinant purified IL-17F/IL-17A heterodimers
(X), similar to IL-17A(♦) and IL-17F (□) homodimers, stimulate GRO-cc levels
(pg/ml) in the media of BJ cell cultures. Figure 19B shows that cotreatment of
BJ cultures with anti-IL-17A antibody (■), or anti-IL-17A in combination with.

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anti-IL-17F antibodies (A), but not IL-17F antibodies alone (□), abrogates IL-
17F/IL-17A heterodimer stimulation of GRO-a levels. Controls consisted of
cultures provided with media lacking both IL-17F and IL-17A antibodies (X).
[0047] Figure 20 is a table summarizing MALDI-TOF mass spectrometry data
for tryptic peptide masses prepared by digestion of IL-17F homodimers, IL-17A
homodimers, and IL-17F/IL-17A heterodirners. The first column of the table
shows the origin of the peptide fragment analyzed, the second column (Structure)
shows the peptide fragment sequence, the third column (MW Cal) shows the
calculated molecular weight of the fragment, the fourth column shows the
calculated mass-to-charge ratio (m/z value) of the fragment (Calculated), and the
fifth column shows the actual mass-to-charge ratio (m/z value) (Observed) as
determined by mass spectrometry.
[0048] Figure 21 shows that anti-human IL-17F antibodies can partially inhibit
the biological activity of primate IL-17F. Figure 21 A and 21B show that BJ
cells stimulated with human or primate (macaque) IL-17F display increased
levels of GRO-a in response to increasing levels of IL-17F. Figure 21A shows
that anti-IL-17F-01 (□) and anti-IL-17F-07 (X) antibodies decrease the ability of
human IL-17F (♦) to stimulate GRO-a levels. Similarly, Figure 21B shows that
anti-IL-17F-01 (□) and anti-IL-17F-07 (X) antibodies decrease the ability of
primate IL-17F (♦) to stimulate GRO- levels, albeit to a lesser extent than the
antibodies reduce human IL-17F biological activity.
[0049] Figure 22 shows that IL-17F treatment increases the expression of
ADAMTS-4 (Aggrecanase 1) in chondrocytes obtained from human donors, and
that treatment with anti-IL-17F antibodies abrogates this stimulation. Cultured
chondrocytes were treated with 250 ng/ml IL-17F, 250 ng/ml IL-17F and 25
g/ml anti-IL-17F, 25 g/ml anti-IL-17F, 250 ng/ml IL-17F and 25 g/ml control
IgGl, or 25 g/ml control IgGl (x-axis), and transcript levels of Aggrecanase 1
measured by real-time PCR (expressed as TAQMAN® units; y-axis). GAPDH
expression levels were used as normalizer.
[0050] Figure 23 shows that treatment of BJ cells with siRNA directed to
transcripts of IL-17R and IL-17RC reduces the ability ofIL-17F and IL-17A to

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increase GRO-a levels Figure 23A: Taqman = % reduction in IL-17R transcript
levels in cells treated with. siRNA to IL-17R; IL-17F = % reduction in the ability
of IL-17F to stimulate GRO-a levels in cells treated with siRNA to IL-17R; IL-
17A = % reduction in the ability of IL-17A to stimulate GRO-a levels in cells
treated with siRNA to IL-17R. Figure 23B shows that treatment of BJ cells with
siRNA directed to transcripts of IL-17RC reduces the ability of IL-17F and IL-
17A to increase GRO-a levels. Taqman = % reduction in IL-17RC transcript
levels in cells treated with siRNA to IL-17R.C; IL-17F = % reduction in the
ability of IL-17F to stimulate GRO-a levels in cells treated with siRNA to IL-
17RC; IL-17A = % reduction in the ability of IL-17A to stimulate GRO-a levels
in cells treated with siRNA to IL-17RC. Figure 23C discloses several siRNA
molecules of the present invention (SEQ ID NOs: 17-32) that target mRNA
polynucleotides related to the present invention (i.e., IL-17R and IL-17RC).
[0051] Figure 24 shows the average fold-change (lesional / nonlesional
(nonaffected) tissues) of IL-17F and IL-17A transcript expression in 48 pairs of
tissue biopsy samples from patients suffering from psoriasis. Both IL-17A and
IL-17F transcript levels are increased in psoriatic lesional tissues with respect to
nonaffected tissue. P-values from paired t-tests are as follows: IL-17A p= 2.8 x
10-13,IL-17Fp=l.lxl0-9.
[0052] Figure 25 shows the average fold-change (involved / noninvolved tissues)
of IL-17F and EL-17A transcript expression in paired tissue biopsy samples from
patients suffering from ulcerative colitis (UC) (□) (12 pairs) or Crohn's disease
(CD) (■) (16 pairs). Both IL-17A and IL-17F transcript levels are increased in
affected tissues relative to noninvolved tissues in both sets of IBD samples.
P-values from paired t-tests are as follows: IL-17A (UC), p=0.309; IL-17A (CD),
p=0,069; IL-17F (UC), p=0.406; IL-17F (CD), p=0.206.
[0053] Figure 26 shows inixaceilular cytokine staining for EL-17F. Staining for
EL-17F was performed on (lymph node) LN cells from C57BL/6 mice immunized
with 100 g ovalbumin emulsified in complete Freund's adjuvant. Cells were
surface-stained for CD4, fixed, permeabilized and stained with an anti-IgGl

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isotype control or with rat anti-murine EL-17F (clone 15-1). Numbers denote
percent of positive cells.
DETAILED DISCRETION OF THE INVENTION
[0054] Interleukin-17F (IL-17F) is a cytokine that belongs to the IL-17 family of
proteins and induces expression of inflammatory cytokines and chsmokines, e.g.,
IL-6, IL-8, GM-CSF, G-CSF, GRO-cc, MCP-1, IL-ip, TNF-a, TGF-p, etc.
Expression of IL-17F is correlated with neutrophilia and various autoimmune
diseases (Bettelli and Kuchroo, supra). For example, IL-17F is associated with
increased proteoglycan breakdown and decreased proteoglycan synthesis by
articular cartilage (Hymowitz, supra), central nervous system autoimmunity
(Langrish, supra), allergic and asthmatic responses (Kawaguchi, supra) and
inflammatory bowel diseases (Gurney, supra). Thus, IL-17F signaling is
believed to be involved with disorders including, but not limited to, inflammatory
disorders, such as autoimmune diseases (e.g:, arthritis (including rheumatoid
arthritis), psoriasis, systemic lupus erythematosus (SLE), multiple sclerosis),
respiratory diseases (e.g., COPD, cystic fibrosis, asthma, allergy), transplant
rejection (including solid organ transplant rejection), and inflammatory bowel
diseases (e.g., ulcerative colitis, Crohn's disease).
[0055] As part of the invention, the inventors have confirmed involvement of
IL-17F in inflammatory disorders by demonstrating the following responses to
administration of IL-17F: e.g., neutrophil influx into the peritoneum (Example
1.1), activation of a primary transcription factor of inflammatory cytokines
correlated with an increased secretion of inflammatory cytokines by primary
chondrocytes (Example 1.2), increased secretion of inflammatory cytokines by
lung fibroblasts (Example 1.3), and increased levels of Aggrecanase in primary
human chondrocytes (Example 7). The inventors have also determined that both
IL-17F and IL-17A may be involved in autoimmune arthritis (Example 7),
psoriasis (Example 9) and inflammatory bowel disease (IBD) (Example 9). The
inventors have also identified IL-17R and H-17RC as receptors for IL-17F
(Example 2), thus providing novel targets for inhibition of the EL-17F signaling
pathway. The inventors have also generated and characterized anti-IL-17F

WO 2006/088833 PCT/US2006/005111
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antibodies in terms of each antibody's binding specificity, affinity, and ability to
inhibit IL-17F signaling, i.e., IL-17F bioactivity (Examples 3 and 5). In one
embodiment, antibodies help to characterize 1L-17F epitopes that maybe
required for IL-17R and/or IL-17RC recognition; i.e., five of six raurine anti-
human IL-17F antibodies are able to interfere with binding of IL-17F to IL-17R,
and two of the five are also able to interfere with binding of IL-17F to IL-17RC.
The inventors have also demonstrated the ability of some of these antibodies to
inhibit (i.e., decrease, limit, block, or otherwise reduce) 3L-17F bioactivities, e.g.,
IL-17F-mediated activation of a primary transcription factor for inflammatory
cytokines, and subsequently, IL-17F-mediated cytoldne secretion by primary
fibroblast-like synoviocytes (Example 4). Also disclosed herein are inhibitory
polynucleotides that decrease IL-17A and EL-17F signaling through the IL-17R
and EL-17RC (Example 8). The inventors have also demonstrated a direct
relationship between IL-21 and IL-17F, i.e., the ability of TL-21 to enhance the
production of both IL-17A and IL-I7F by activated T cells. Thus, it is reasoned
that inhibition of IL-17F signaling may also inhibit at least one effect associated
with IL-2I binding to and activation of IL-21R, e.g., methods of inhibiting
IL-17F signaling maybe used in methods of treating IL-17F-associated disorders
and/or disorders associated with IL-21 binding to and activating IL-21R. The
inventors also isolated for the first time IL-17A and IL-17F from the cytokines'
natural source. The inventors have also demonstrated and purified a novel
IL-17A/IL-17F heterodimer (e.g., in T cells, and HEK-293 and COS cells,
respectively), and have shown that the heterodimer transduces IL-17F signaling,
e.g., by inducing expression of GRO-a levels (Example 5). Thus the inventors
have provided the heterodimer as a novel target for inhibition of the IL-17F-
signaling pathway and/or in the treatment of inflammatory disorders and/or
disorders associated with IL-21 binding to and activating IL-21R.
[0056] As such, the present invention provides IL-17F signaling antagonists,
(e.g., IL-17F, IL-17R, and/or IL-17RC inhibitory polynucleotides; soluble
IL-17R and/or IL-17RC polypeptides (including fragments (e.g., IL-17F binding
fragments) and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or
IL-17RC antibodies; and/or antagonistic small molecules), which may be used to

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suppress IL-17F-mediated (including IL-17F homodimer- and IL-17A/EL-17F
heterodimer-mediated) inflammatory responses in vivo, and consequently, which
may be used in the diagnosis, prognosis, monitoring and/or treatment of disorders
related to increased IL-17F signaling, i.e., IL-17F-associated disorders and/or
disorders associated with EL-21 binding to and activating IL-21R. The
identification and isolation of the novel IL-17A/IL-17F heterodimer indicates that
disorders related to IL-17F signaling may be mediated by IL-17F homodimers
and/or IL-17F heterodimers. Thus the term "IL-17F" as used herein, where
appropriate, refers to IL-17F homodimers or IL-17A/IL-17F heterodimers, e.g.,
the IL-17F signaling pathway encompasses a signaling pathway that may
comprise either or both IL-17F homodimers and EL-17A/IL-17F heterodimers.
[0057] Accordingly, the present application provides IL-17F signaling-related
polynucleotides and polypeptides, including IL-17R and IL-17RC
polynucleotides and polypeptides. The present invention also provides
antibodies, i.e., intact antibodies and antigen-binding fragments thereof, that bind
to IL-17F, in particular, human IL-17F, including, but not limited to, IL-17F
homodimers and IL-17A/rL-17F heterodimers. In one embodiment, an anti-
IL-17F antibody inhibits or antagonizes at least one IL-17F-associated (e.g.,
IL-17F homodimer and/or IL-17A/IL-17F heterodimer) activity. For example,
the anti-IL-17F antibody can bind to IL-17F and interfere with, e.g., block, an
interaction between IL-17F and an TL-17F receptor complex, e.g., complexes
comprising IL-17R and/or IL-17RC. Thus, the antibodies of the invention may
be used detect, and optionally inhibit (e.g., decrease, limit, block or otherwise
reduce), an IL-17F bioactivity, e.g., binding between IL-17F and an IL-17F
receptor complex, or subunit thereof. Thus, the anti-IL-17F antibodies of the
invention may be used to diagnose, prognose, monitor and/or treat or prevent
disorders related to IL-17F signaling and/or disorders associated with IL-21
binding to and activating IL-2IR.
Polynucleotides and Polypeptides of IL-17F, IL-17R, and IL-17RC
[0058] The present invention provides further characterization of the IL-17F
signaling pathway, i.e., determination of IL-17R and/or IL-17RC as an IL-17F

WO 2006/088833 PCT/US2006/005111
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receptor, elucidation of the effects of interfering with IL-17F binding to IL-17R
and/or IL-17RC using inhibitory molecules, e.g., antibodies, receptor fusion
proteins and siRNA, and the purification of IL-17A/IL-17F heterodimers. As
such, the present invention relates to IL-17F, IL-17R, and IL-17R.C
polynucleotides and porypeptides, including inhibitory IL-17F, IL-17R and
IL-17RC polynucleotides and polypeptides.
[0059] IL-17F nucleotide and amino acid sequences are known in the art and are
provided. The nucleotide sequence of human IL-17F is set forth in SEQ ID
NO:1. The amino acid sequence of full-length IL-17F protein coded by that
nucleotide sequence is set forth in SEQ ID NO:2. The amino acid sequence of
mature IL-17F corresponds to a protein beginning at about amino acid 31 of SEQ
ID NO:2 (see, e.g., U.S. Patent Application No. 10/102,080, incorporated herein
in its entirety by reference).
[0060] IL-17A nucleotide and amino acid sequences are known in the art and are
provided. The nucleotide sequence of human IL-17A is set forth in SEQ ID
NO:3, which includes apo!y(A) tail. The amino acid sequence of full-length
IL-17A protein corresponding to that nucleotide sequence is set forth in SEQ ID
NO.4.
[0061] IL-17R nucleotide and amino acid sequences are known in the art and are
provided. The nucleotide sequence of human IL-17R is set forth as SEQ ID
NO:5, which includes apoly(A) tail. The amino acid sequence of full-length
EL-17R protein corresponding to that nucleotide sequence is set forth in SEQ ID
NO:6.
[0062] IL-17RC nucleotide and amino acid sequences are known in the art and
are provided. The nucleotide sequences of several human IL-17RC
polynucleotides, which include poly(A) tails, are set forth as SEQ ID NOs:7, 9,
11, 13, and 15. The amino acid sequences of several full-length human IL-17RC
proteins corresponding to those nucleotide sequences are set forth in SEQ ID
NOs:8,10,12,14, and 16.
[0063] The nucleic acids related to the present invention may comprise DNA or
RNA and may be wholly or partially synthetic. Reference to a nucleotide

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sequence as set forth herein encompasses a DNA molecule with the specified
sequence (or a complement thereof), and encompasses an RNA molecule with the
specified sequence in which U is substituted for T, unless context requires
otherwise.
[0064] The isolated polynucleotides related to the present invention may be used
as hybridization probes and primers to identify and isolate nucleic acids having
sequences identical to or similar to those encoding the disclosed polynucleotides.
Hybridization methods for identifying and isolating nucleic acids include
polymerase chain reaction (PCR), Southern hybridization, in situ hybridization
and Northern hybridization, and are well known to those skilled in the art.
[0065] Hybridization reactions may be performed under conditions of different
stringency. The stringency of a hybridization reaction includes the difficulty with
which any two nucleic acid molecules will hybridize to one another. Preferably,
each hybridizing polynucleotide hybridizes to its corresponding polynucleotide
under reduced stringency conditions, more preferably stringent conditions, and
most preferably highly stringent conditions. Examples of stringency conditions
are shown in Table 1 below: highly stringent conditions are those that are at least
as stringent as, for example, conditions A-F; stringent conditions are at least as
stringent as, for example, conditions G-L; and reduced stringency conditions are
at least as stringent as, for example, conditions M-R.
Table I. Stringency Conditions


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I: The hybrid length is that anticipated for the hybridized region(s) of the hybridizing polynucleotides. When
hybridizing a polynucleotide to a target polynucleotide of unknown sequence, the hybrid length is assumed to
be that of the hybridizing polynucleotide. When polynucleotides of known sequence are hybridized, the
hybrid length can be determined by aligning the sequences of the polynucleotides and identifying the region or
regions of optimal sequence complementarity.
2: SSPE (lxSSPE is 0.15M NaCl, 10mM NaH2PO4> and 1.25mM EDTA, pH 7.4) can be substituted for SSC
(ixSSC is 0.15M NaCl and 15mM sodium citrate) in the hybridization and wash buffers; washes are
performed for 15 minutes after hybridization is complete.
Tn* - TR*: The hybridization temperature for hybrids anticipated to be less than 50 base pairs in length should
be 5-10°C less than the melting temperature (Tm) of the hybrid, where Tm is determined according to the
following equations. For hybrids less than 18 base paiis in length, Tm(°C) = 2(# of A + T bases) + 4(# of G +
C bases). For hybrids between 18 and 49 base pairs in length, Tm(°C) = 81.5 + \6.6(log10Na4) + 0.41 (%G+C) -
(600/N), where N is the number of bases in the hybrid, and Na+ is the concentration of sodium ions in the
hybridization buffer (Na+ for 1 xSSC = 0.165M).

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Additional examples of stringency conditions forpolynudeotidehybridization are provided in Sambrook, J.,
E.F. Fritsch, and T. Maniatis, 1989, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, NY, chapters 9 and 11, and Current Protocols in Molecular Biology,
1995, F.M. Ausubel et a]., eds., John Wiley & Sons, Inc., sections 2.10 and 6.3-6.4, incorporated herein by
reference.
[0066] The isolated polynucleotides related to the present invention may be used
as hybridization probes and primers to identify and isolate DNA having
sequences encoding allelic variants of the disclosed polynucleotides. Allelic
variants are naturally occurring alternative forms of the disclosed polynucleotides
that encode polypeptides that are identical to or have significant similarity to the
polypeptides encoded by the disclosed polynucleotides. Preferably, allelic
variants have at least 90% sequence identity (more preferably, at least 95%
identity; most preferably, at least 99% identity) with the disclosed
polynucleotides. Alternatively, significant similarity exists when the nucleic acid'
segments will hybridize under selective hybridization conditions (e.g., highly
stringent hybridization conditions) to the disclosed polynucleotides.
[0067] The isolated polynucleotides related to the present invention may also be
used as hybridization probes and primers to identify and isolate DMAs having
sequences encoding polypeptides homologous to the disclosed polynucleotides.
These homologs are polynucleotides and polypeptides isolated from a different
species than that of the disclosed polypeptides and polynucleotides, or within the
same species, but with significant sequence similarity to the disclosed
polynucleotides and polypeptides. Preferably, polynucleotide homologs have at
least 50% sequence identify (more preferably, at least 75% identity; most
preferably, at least 90% identity) with the disclosed polynucleotides, whereas
polypeptide homologs have at least 30% sequence identify (more preferably, at
least 45% identify; most preferably, at least 60% identify) with the disclosed
polypeptides. Preferably, homologs of the disclosed polynucleotides and
polypeptides are those isolated from mammalian species.
[0068] Calculations of "homology" or "sequence identify" between two
sequences (the terms are used interchangeably herein) are performed as follows.
The sequences are aligned for optimal comparison purposes (e.g., gaps can be

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introduced in one or both of a first and a second amino acid or nucleic acid
sequence for optimal alignment and nonhomologous sequences can be
disregarded for comparison purposes). In a preferred embodiment, the length of
a reference sequence aligned for comparison purposes is at least 30%, preferably
at least: 40%, more preferably at least 50%, even more preferably at least 60%,
and even more preferably at least 70%, 80%, 90%; 100% of the length of the
reference sequence. The amino acid residues or nucleotides at corresponding
amino acid positions or nucleotide positions are then compared. When a position
in the first sequence is occupied by the same amino acid residue or nucleotide as
the corresponding position in the second sequence, then the molecules are
identical at that position (as used herein amino acid or nucleic acid "identity" is
equivalent to amino acid or nucleic acid "homology"). The percent identity
between the two sequences is a function of the number of identical positions
shared by the sequences, taking into account the number of gaps, and the length
of each gap, which need to be introduced for optimal alignment of the two
sequences.
[0069] The comparison of sequences and determination of percent sequence
identity between two sequences may be accomplished using a mathematical
algorithm. In a preferred embodiment, the percent identity between two amino
acid sequences is determined using the Needleman and Wunsch ((1970) /. Mol.
Biol. 48:444-53) algorithm, which has been incorporated into the GAP program
in the GCG software package (available at www.gcg.com), using either a
Blossum 62 matrix or a PAM250 matrix, and a gap weight of 16,14,12,10, 8,6,
or 4 and a length weight of 1,2,3,4,5, or 6. In yet another preferred
embodiment, the percent identity between two nucleotide sequences is
determined using the GAP program in the GCG software package (available at
www.gcg.com), using a NWSgapdna.CMP matrix and a gap weight of 40,50,60,
70, or 80 and a length weight of 1,2,3,4,5, or 6. A particularly preferred set of
parameters (and the one that should be used if the practitioner is uncertain about
what parameters should be applied to determine whether a molecule is within a
sequence identity or homology limitation of the invention) is a Blossum 62
scoring matrix with a gap penalty of 12, a gap extend penalty of 4, and a

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frameshift gap penalty of 5. The percent identity between two amino acid or
nucleotide sequences can also be determined using the algorithm of Meyers and
Miller ((1989) CABIOS 4:11-17), which has been incorporated into the ALIGN
program (version 2.0), using a PAMI 20 weight residue table, a gap length
penalty of 12 and a gap penalty of 4.
[0070] The isolated polynucleotides related to the present invention may also be
used as hybridization probes and primers to identify cells and tissues that express
the polypeptides related to the present invention and the conditions under which
they are expressed.
[0071] Additionally, the function of the polypeptides related to the present
invention may be directly examined by using the polynucleotides encoding the
polypeptides to alter (i.e., enhance, reduce, or modify) the expression of the genes
corresponding to the polynucleotides related to the present invention in a cell or
organism. These "corresponding genes" are the genomic DNA sequences related
to the present invention that are transcribed to produce the mRNAs from which
the polynucleotides related to the present invention are derived.
[0072] Altered expression of the genes related to the present invention may be
achieved in a cell or organism through the use of various inhibitory
polynucleotides, such as antisense polynucleotides, siRNAs, and ribozymes that
bind and/or cleave the mRNA transcribed from the genes related to the invention
(see, e.g., Galderisi et al. (1999)/. CellPhysiol 181:251-57; Sioud (2001) Curr.
Mol Med. 1:575-88). Inhibitory polynucleotides to, e.g., IL-17F, IL-17R, and/or
IL-17RC, maybe useful as IL-17F signaling antagonists and, as such, may also
be useful in preventing or treating disorders related to IL-17F signaling.
Inhibitory polynucleotides may also consist of aptamers, i.e., polynucleotides that
bind to and regulate protein activity, e.g., the activity of IL-17F, EL-17A, IL-17R,
and/or IL-17RC. Aptamers are described throughout the literature, see, e.g.,
Nimjee et al. (2005) Anmi. Rev. Med. 56:555-83 and Patel (1997) Curr. Opm.
Chem. Biol. 1:32-46.
[0073] The antisense polynucleotides or ribozymes related to the invention may
be complementary to an entire coding strand of a gene related to the invention, or

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to only a portion thereof. Alternatively, antisense polynucleotides or ribozymes
can be complementary to a noncoding region of the coding strand of a gene
related to the invention. The antisense polynucleotides or ribozymes can be
constructed using chemical synthesis and enzymatic ligation reactions using
procedures well known in the art. The nucleoside linkages of chemically
synthesized polynucleotides can be modified to enhance their ability to resist
nuclease-mediated degradation, as well as to increase their sequence specificity.
Such linkage modifications include, but are not limited to, phospborothioate,
methylphosphonate, phosphoroamidate, boranophosphate, morpholino, and
peptide nucleic acid (PNA) linkages (Galderisi et al., supra; Heasman (2002)
Dev. Biol 243:209-14; Micklefield (2001) Curr. Med. Chem. 8:1157-79).
Alternatively, these molecules can be produced biologically using an expression
vector into which a polynucleotide related to the present invention has been
subcloned in an antisense (i.e., reverse) orientation.
[0074] The inhibitory polynucleotides of the present invention also include
triplex-forming oligonucleotides (TFOs) that bind in the major groove of duplex
DNA with high specificity and affinity (Knauert and Glazer (2001) Hum. Mol.
Genet. 10:2243-51). Expression of the genes related to the present invention can
be inhibited by targeting TFOs complementary to the regulatory regions of the
genes (i.e., the promoter and/or enhancer sequences) to form triple helical
structures that prevent transcription of the genes.
[0075] In one embodiment of the invention, the inhibitory polynucleotides of the
present invention are short interfering RNA (siRNA) molecules. These siRNA
molecules are short (preferably 19-25 nucleotides; most preferably 19 or 21
nucleotides), double-stranded RNA molecules that cause sequence-specific
degradation of target mRNA. This degradation is known as RNA interference
(RNAi) (e.g., Bass (2001) Nature 411:428-29). Originally identified in lower
organisms, RNAi has been effectively applied to mammalian cells and has
recently been shown to prevent fulminant hepatitis in mice treated with siRNA
molecules targeted to Fas mRNA (Song et al. (2003) Nature Med. 9:347-51). In
addition, intrathecally delivered siRNA has recently been reported to block pain

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responses in two models (agonist-induced pain model and neuropathic pain
model) in the rat (Dorn et al. (2004) Nucleic Acids Res. 32(5):e49).
[0076] The siRNA molecules of the present invention may be generated by
annealing two complementary single-stranded RNA molecules together (one of
which matches a portion of the target mRNA) (Fire et al., U.S. Patent No.
6,506,559) or through the use of a single hairpin RNA molecule that folds back
on itself to produce the requisite double-stranded portion (Yu et al. (2002) Proc.
Natl.Acad. Set USA 99:6047-52). The siKNA molecules may be chemically
synthesized (Elbashir et al. (2001) Nature 411:494-98) or produced by in vitro
transcription using single-stranded DNA templates (Yu et al., supra).
Alternatively, the siRNA molecules can be produced biologically, either
transiently (Yu et al., supra; Sui et al. (2002) Proc. Nat!. Acad. Sci. USA
99:5515-20) or stably (Paddison et al. (2002) Proc. Natl. Acad. Sci. USA
99:1443-48), using an expression vector(s) containing the sense and antisense
siRNA sequences. Recently, reduction of levels of target mRNA in primary
human cells, in an efficient and sequence-specific manner, was demonstrated
using adenoviral vectors that express hairpin RNAs, which are further processed
into siRNAs (Arts et al. (2GQ3),Genome Res. 13:2325-32).
[0077] The siRNA molecules targeted to the polynucleotides related to the
present invention can be designed based on criteria well known in the art (e.g.,
Elbashir et al. (2001) EMBO J. 20:6877-88). For example, the target segment of
the target mRNA preferably should begin with AA (most preferred), TA, GA, or
CA; the GC ratio of the siRNA molecule preferably should be 45-55%; the
siRNA molecule preferably should not contain three of the same nucleotides in a
row; the siRNA molecule preferably should not contain seven mixed G/Cs in a
row; and the target segment preferably should be in the ORF region of the target
mRNA and preferably should be at least 75 bp after the initiation ATG and at
least 75 bp before the stop codon. Based on these criteria, or on other known
criteria (e.g., Reynolds et ai. (2004) NatureBiotechnol. 22:326-30), siRNA
molecules of the present invention that target the mRNA polynucleotides related
to the present invention may be designed by one of ordinary skill in the art.
Preferred examples of siRNAs for use in the disclosed methods are set forth in

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SEQ ID NOs:17-32 and correspond to siRNAs useful to target IL-17R (SEQ ID
NOs:17-24) and IL-17RC (SEQ ID NOs:25-32).
[0078] Altered expression of the genes related to the present invention in an
organism may also be achieved through the creation of nonhuman transgenic
animals into whose genomes polynucleotides related to the present invention
have been introduced. Such transgesic animals include animals that have
multiple copies of a gene (i.e., the transgene) of the present invention. A tissue-
specific regulatory sequence(s) may be operably linked to the transgene to direct
expression of a polypeptide related to the present invention to particular cells or a
particular developmental stage. Methods for generating transgenic animals via
embryo manipulation and microinjection, particularly animals such as mice, have
become conventional and are well known in the art (e.g., Bockamp et al., Physiol.
Genomics 11:115-32 (2002)).
[0079] Altered expression of the genes related to the present invention in an
organism may also be achieved through the creation of animals whose
endogenous genes corresponding to the polynucleotidcs related to the present
invention have been disrupted through, insertion of extraneous polynucleotide
sequences (i.e., a knockout animal). The coding region of the endogenous gene
maybe disrupted, thereby generating a nonfunctional protein. Alternatively, the
upstream regulatory region of the endogenous gene may be disrupted or replaced
with different regulatory elements, resulting in the altered expression of the still-
functional protein. Methods for generating knockout animals include
homologous recombination and are well known in the art (e.g., Wolfer et al.,
Trends Neurosci. 25:336-40 (2002)).
[0080] The isolated polynucleotides of the present invention also may be
operably linked to an expression control sequence and/or ligated into an
expression vector for recombinant production of the polypeptides (including
active fragments and/or fusion polypeptides thereof) related to the present
invention. General methods of expressing recombinant proteins are well known
in the art.

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[0081] An expression vector, as used herein, is intended to refer to a nucleic acid
molecule capable of transporting another nucleic acid to which it has been linked.
One type of vector is a plasmid, which refers to a circular double stranded DNA
loop into which additional DNA segments may be ligated. Another type of
vector is a viral vector, wherein additional DNA segments may be ligated into the
viral genome. Certain vectors are capable of autonomous replication in a host
cell into which they are introduced (e.g., bacterial vectors having a bacterial
origin of replication and episomal mammalian vectors). Other vectors (e.g.,
nonepisomal mammalian vectors) can be integrated into the genome of a host cell
upon introduction into the host cell, and thereby are replicated along with the host
genome. Moreover, certain vectors are capable of directing the expression of
genes to which they are operably linked. Such vectors are referred to herein as
recornbinant expression vectors (or simply, expression vectors). In general,
expression vectors of utility in recombinant DNA techniques are often in the
form of plasmids. In the present specification, plasmid and vector may be used
interchangeably as the plasmid is the most commonly used form of vector.
However, the invention is intendedto include other forms of expression vectors,
such as viral vectors (e.g., replication defective retroviruses, adenoviruses and
adeno-associated viruses) that serve equivalent functions.
[0082] In one embodiment, the polynucleotides related to the present invention
are used to create recombinant IL-17F agonists, e.g., those that can be identified
based on the presences of at least one "IL-17F receptor-binding motif." As used
herein, the term "IL-17F receptor-binding.motif" includes amino acid sequences
or residues that are important for binding of IL-17F to its requisite receptor. An
example of an IL-17F agonist includes IL-17F homodirner, IL-17A/IL-17F
heterodimer, fragments thereof, e.g., IL-17R or IL-17RC binding fragments,
and/or small molecules (as described below). Such agonists may be useful in
regulation of hematopoiesis, and consequently, in the treatment of myeloid or
lymphoid cell deficiencies. In another embodiment, the polynucleotides related
to the present invention are used to create IL-17F signaling antagonists (e.g.,
IL-17F, IL-17R, and/or IL-17RC inhibitory polynucleotides; soluble IL-17R
and/or IL-17RC polypeptides (including fragments (e.g., IL-17F binding

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fragments) and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or
IL-17RC antibodies, which may inhibit the bioactivity of IL-17F homodimers
and/or IL-17A/IL-17F heterodimers; and/or antagonistic small molecules, etc.).
[0083] Methods of creating fusion polypeptides, i.e., a first polypeptide moiety
linked with a second polypeptide moiety, are well known in the art. For example,
an IL-17F polypeptide or an IL-17F receptor polypeptide (e.g., IL-17R and/or
IL-17RC, including fragments thereof) may be fused to a second polypeptide
moiety, e.g., an imrnunoglobnlin or a fragment thereof (e.g., an Fc binding
fragment thereof). In some embodiments, the first polypeptide moiety includes,
e.g., full-length IL-I7RC polypeptide. Alternatively, the first polypeptide may
comprise less than the full-length IL-17RC polypeptide. Additionally, soluble
forms of, e.g., IL-17RC may be fused, through "linker" sequences to the Fc
portion of an irnmunoglobulin. Other fusions proteins, such as those with
glutathione-S-transferase (GST), Lex-A, tbioredoxin (TRX) or maltose-binding
protein (MBP), may also be used.
[0084] The second polypeptide moiety is preferably soluble. In some
embodiments, the second polypeptide moiety enhances the half-life, (e.g., the
serum half-life) of the linked polypepiide. In some embodiments, the second
polypeptide moiety includes a sequence that facilitates association of the fusion
polypeptide with a second IL-17F or IL-17R polypeptide. In preferred
embodiments, the second polypeptide includes at least a region of an
irnmunoglobulin polypeptide. Irnmunoglobulin fusion polypeptide are known in
the art and are described in, e.g., U.S. Patent Nos. 5,516,964; 5,225,538;
5,428,130; 5,514,582; 5,714,147; and 5,455,165, all of which are hereby
incorporated by reference. The fusion proteins may additionally include a linker
sequence joining the first polypeptide moiety, e.g., IL-17F or IL-17R, including
fragments thereof, to the second moiety. Use of such linker sequences are well
known in the art. For example, the fusion protein can include a peptide linker,
e.g., a peptide linker of about 2 to 20. more preferably less than 10, amino acids
in length. In one embodiment, the peptide linker may be 2 amino acids in length.

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[0085] In another embodiment, the recombinant protein includes a heterologous
signal sequence (i.e., a polypeptide sequence that is not present in apolypeptide
encoded by an IL-17F, IL-17R or IL-17RC nucleic acid) at its N-terminus. For
example, a signal sequence from another protein may be fused with an IL-17R
and/or IL-17RC polypeptide, including fragments and/or fusion proteins thereof.
In certain host cells (e.g.. mammalian host cells), expression and/or secretion of
recombinant proteins can be increased through use of a heterologous signal
sequence. A signal peptide that may be included in the fusion protein is the
melittin signal peptide MKFLVNVALVFMWYISYIYA (SEQ ID NO.33).
[0086] A fusion protein of the invention may be produced by standard
recombinant DNA techniques. For example, DNA fragments coding for the
different polypeptide sequences are ligated together in-frame in accordance with
conventional techniques by employing, e.g., blunt-ended or stagger-ended termini
for ligation, restriction enzyme digestion to provide for appropriate termini,
filling-in of cohesive ends as appropriate, alkaline phosphatase treatment to avoid
undesirable joining, and enzymatic ligation. In another embodiment, the- fusion
gene can be synthesized by conventional techniques including automated DNA
synthesizers. Alternatively, PCR amplification of gene fragments may be carried
out using anchor primers that give rise to complementary overhangs between two
consecutive gene fragments that can subsequently be annealed and reamplified to
generate a chimeric gene sequence (see, for example, Ausubel et al. (Eds.)
Current Protocols in Molecular Biology, John Wiley & Sons, 1992). Moreover,
many expression vectors are commercially available that encode a fusion moiety
(e.g., an Fc region of an immunoglobulin heavy chain). An IL-17F-, IL-17R-
and/orIL-17RC-encoding nucleic acid maybe cloned into such an expression
vector such that the fusion moiety is linked in-frame to the immunoglobulin
protein. In some embodiments, IL-17F, IL-17R and/or IL-17RC fusion
polypeptides exist as oligomers, such as dimers or trimers.
[0087] The recombinant expression vectors of the invention may carry additional
sequences, such as sequences that regulate replication of the vector in host cells
(e.g., origins of replication) and selectable marker genes. The selectable marker
gene facilitates selection of host cells into which the vector has been introduced.

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For example, typically the selectable marker gene confers resistance to drugs,
such as G418, hygromycin or methotrexate, on a host cell into which the vector
has been introduced. Preferred selectable marker genes include the dihydrofolate
reductase (DHFR) gene (for use in dhfr host cells with methotrexate
selection/amplification) and the neo gene (for G418 selection).
[0088] Suitable vectors can be chosen or constructed, containing appropriate
regulatory sequences, including promoter sequences, terminator sequences,
polyadenylation sequences, enhancer sequences, marker genes and other
sequences, e.g., sequences that regulate replication-of the vector in the host cells
(e.g., origins of replication) as appropriate. Vectors may be plasmids or viral,
e.g., phage, or phagemid, as appropriate. For further details see, for example,
Molecular Cloning: a Laboratory Manual: 2nd ed., Sambrook et al., Cold Spring
Harbor Laboratory Press, 1989. Many known techniques and protocols for
manipulation of nucleic acid, for example, in preparation of nucleic acid
constructs, mutagenesis, sequencing, introduction of DNA into cells and gene
expression, and analysis of proteins, are described in detail in Current Protocols
in Molecular Biology, 2nd ed., Ausubel et al. eds., John Wiley & Sons, 1992.
[0089] Thus, a further aspect of the present invention provides a host cell
comprising a nucleic acid as disclosed herein. A still further aspect provides a
method comprising introducing such nucleic acid into a host cell. The
introduction may employ any available technique. For eukaryotic cells, suitable
techniques may include calcium phosphate transfection, DEAE-Bextran,
electroporation, liposome-mediated transfection, and transduciion using
retrovirus or other viruses, e.g., vaccinia or, for insect cells, baculovirus. For
bacterial cells, suitable techniques may include calcium chloride transformation,
electroporation and transfection using bacteriophage. The introduction may be
followed by causing or allowing expression from the nucleic acid, e.g., by
culturing host cells under conditions for expression of the gene.
[0090] A number of cell lines may act as suitable host cells forrecombinant
expression of the polypeptides related to the present invention. Mammalian host
cell lines include, for example, COS cells, CHO cells, 293 cells, A431 cells, 3T3

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cells, CV-1 cells, HeLa cells, L cells, BHK21 cells, HL-60 cells, U937 cells, HaK
cells, Jurkat cells, as well as cell strains derived from in vitro culture of primary
tissue and primary explants.
[0091] Alternatively, it may be possible to recombinantly produce the
polypeptides related to the present invention in lower eukaryotes, such as yeast,
or in prokaryotes. Potentially suitable yeast strains include Saccharomyces
cerevisiae, Schizosaccharomycespom.be, Kluyveromyces strains, and Candida
strains. Potentially suitable bacterial strains include Escherichia coli, Bacillus
subtilis, and Salmonella typhimurium. If the polypeptides related to the present
invention are made in yeast or bacteria, it may be necessary to modify them by,
for example, phosphorylation or glycosylation of appropriate sites, in order to
obtain functionality. Such covalent attachments may be accomplished using
well-known chemical or enzymatic methods.
[0092] Expression in bacteria may result in formation of inclusion bodies
incorporating the recombinant protein. Thus, refolding of the recombinant
protein may be required in order to produce active or more active material.
Several methods for obtaining correctly folded heterologous proteins from
bacterial inclusion bodies are known in the art. These methods generally involve
solubilizing the protein from the inclusion bodies, then denaturing the protein
completely using a chaotropic agent. When cysteine residues are present in the
primary amino acid sequence of the protein, it is often necessary to accomplish
the refolding in an environment that allows correct formation of disulfide bonds
(a redox system). General methods of refolding are disclosed in Kohno (1990)
Meth. Enzymol 185:187-95. EP 0433225, and U.S. Patent 5,399,677 describe
other appropriate methods.
[0093] The polypeptides related to the present invention may also be
recombinantly produced by operably linking the isolated polynucleotides of the
present invention to suitable control sequences in one or more insect expression
vectors, such as baculovirus vectors, and employing an insect cell expression
system. Materials and methods for baculovirus/Sf9 expression systems are

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commercially available in kit form (e.g., MAXBAC® kit, Invitrogen, Carlsbad,
CA).
[0094] Following recombinant expression in the appropriate host cells, the
recombinant polypeptides of the present invention may then be purified from
culture medium or cell extracts using known purification processes, such as
immunoprecipitation, gel filtration and ion exchange chromatography. For
example, soluble forms of IL-17F signaling antagonists, e.g., IL-17R protein
and/or IL-17RC proteins (including fragments, and/or fusion proteins thereof); or
IL-17F agonists, e.g., soluble IL-17F (in homodimer or IL-17A/IL-17F
heterodimer formation), may be purified from conditioned media. Membrane-
bound forms of, e.g., an IL-17F signaling antagonist, maybe purified by
preparing a total membrane fraction from the expressing cell and extracting the
membranes with a nonionic detergent such as Triton X-100. A polypeptide
related to the present invention maybe concentrated using a commercially
available protein concentration filter, for example, an AMICON® or Millipore
PELLICON® ultrafiltration unit (Millipore, Billerica, MA), Following the
concentration step, the concentrate can be applied to a purification matrix such as
a gel filtration medium. Alternatively,.an anion exchange resin can be employed,
for example, a matrix or substrate having pendant diethylaminoethyl (DEAE) or
polyetheyleneimine (PEI) groups. The matrices can be acrylamide, agarose,
dextran, cellulose or other types commonly employed in protein purification.
Alternatively, a cation exchange step can be employed. Suitable cation
exchangers include various insoluble matrices comprising sulfopropyl or
carboxymethyl groups. Sulfopropyl groups are preferred (e.g., S-SEPHAROSE®
columns, Sigma-Aldrich, St. Louis, MO). The purification of recombinant
proteins from culture supernatant may also include one or more column steps
over such affinity resins as concanavalin A-agarose, heparin-TOYOPEARL®
(Toyo Soda Manufacturing Co., Ltd., Japan) or Cibacrom blue 3GA
SEPHAROSE® (Tosoh Biosciences, San Francisco, CA); or by hydrophobic
interaction chromatography using such resins as phenyl ether, butyl ether, or
propyl ether; or by immunoafflnity chromatography. Finally, one or more
reverse-phase high performance liquid chromatography (RP-HPLC) steps

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employing hydrophobic RP-HPLC media, e.g., silica gel having pendant methyl
or other aliphatic groups, can be employed to further purify the recombinant
protein. Affinity columns including antibodies (e.g., those described using the
methods herein) to the recombinant protein may also be used in purification in
accordance with known methods. Some or all of the foregoing purification steps,
in various combinations or with other known methods, may also be employed to
provide a substantially purified isolated recombinant protein. Preferably, the
isolated recombinant protein is purified so that it is substantially free of other
mammalian proteins. Additionally, these purification processes may also be used
to purify the polypeptides of the present invention from other sources, including
natural sources. For example, polypeptides related to the invention, e.g., IL-17F
agonists (e.g., soluble IL-17F) or IL-17F signaling antagonists (e.g., soluble
IL-17R and/or soluble IL-17RC proteins, including fragments and/or fusion
proteins thereof), which are expressed as a product of transgenic animals, e.g., as
a component of the milk of transgenic cows, goats, pigs, or sheep, may be
purified as described above.
[0095] Alternatively, the polypeptides may also be recombinantly expressed in a
form that facilitates purification. For example, the polypeptides may be
expressed as fusions with proteins such as maltose-binding protein (MBP),
glutathione-iS'-transferase (GST), or thioredoxin (TRX). Kits for expression and
purification of such fusion proteins are commercially available from New
England BioLabs (Beverly, MA), Pharmacia (Piscataway, NJ), and Invitrogen,
respectively. Recombinant proteins can also be tagged with a small epitope and
subsequently identified or purified using a specific antibody to the epitope. A
preferred epitope is the FLAG epitope, which is commercially available from
Eastman Kodak (New Haven, CT).
[0096] Alternatively, recombinant IL-17F and IL-17A fusion proteins may be
tagged with different epitopes to allow purification of IL-17A/IL-17F
heterodirners. The existence of different tags on IL-17F and IL-17A allows
isolation of IL-17A/IL-17F heterodimers that are substantially free from both IL-
17A and IL-17F homodimers. For example, 1L-17A may be tagged with an
epitope such as FLAG or myc epitope, while IL-17F is concurrently tagged with

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an epitope such as His or GST epitope, and both proteins simultaneously
expressed in a cell. Extracts from the recombinant host cell, or media in which
the host cells are cultured, would be obtained and subjected to two-step affinity
chromatography purification under nonreducing conditions. The first affinity
column would bind one of the two different tags, e.g., a FLAG epitope fused to
IL-17A (or a fragment of IL-17A), and therefore the wash from the first column
would contain (predominantly) IL-17F homodimers and the eluent from the first
column would contain both IL-17A/1L-17F heterodimers and IL-17A
homodimers. The eluent from the first column would then be placed over a
second affinity column that specifically binds the other of the two different tags,
e.g., a His tag fused to IL-17F. Thus, the wash from the second column would
contain IL-17A homodimers and the eluent from the second column would
predominantly or exclusively contain IL-17A/IL-17F heterodimers (i.e.,
substantially free of both IL-17A and IL-17F homodimers). The extracts from
the recombinant host cells or the host cell media could be obtained under
nonreducing conditions such that protein-protein interactions are not interrupted,
or could be obtained under reducing conditions and then treated to allow proper
refolding and interactions of the IL-17F and IL-17A monomers contained therein.
One skilled in the art would readily realize that a host cell need not express both
IL-17F and IL-17A fusion proteins; rather cell or media extracts from single
transfectants, e.g., a host cell expressing either a IL-17A or IL-17F fusion protein,
could be obtained and combined under conditions that allow the IL-17A and IL-
17F monomers to dimerize.
[0097] The polypeptides related to the present invention, including IL-17F
signaling antagonists, may also be produced by known conventional chemical
synthesis. Methods for chemically synthesizing such polypeptides are well
known to those skilled in the art. Such chemically synthetic polypeptides may
possess biological properties in common with the natural, purified polypeptides,
and thus may be employed as biologically active or immunological substitutes for
the natural polypeptides.
[0098] The inventors were also able to isolate the "natural", i.e., nonrecombinant
form, of the polypeptides of the invention, including a natural form of IL-17A

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(see, e.g., Example 5). Thus, the polypeptides of the present invention include
natural XL-17Ahomodimer, IL-17F homodimer, IL-17A/IL-17F heterodimer, etc.
[0099] The polypeptides related to the present invention, including IL-17F
signaling antagonists, also encompass molecules that are structurally different
from the disclosed polypeptides (e.g., which have a slightly altered sequence), but
have substantially the same biochemical properties as the disclosed polypeptides
(e.g., are changed only in functionally nonessential amino acid residues). Such
molecules include naturally occurring allelic variants and deliberately engineered
variants containing alterations, substitutions, replacements, insertions, or
deletions. Techniques for such alterations, substitutions, replacements,
insertions, or deletions are well known to those skilled in the art. In some
embodiments, the polypeptide moiety is provided as a variant polypeptide having
mutations in the naturally occurring sequence (wild type) that results in a
sequence more resistant to proteolysis (relative to the nonmutated sequence).
[0100] IL-17F (including IL-17F homodimers and IL-17A/IL-17F heterodimcrs),
IL-17R, IL-17RC polypeptides, fragments and/or fusion polypeptides thereof,
recombinant and natural forms thereof, and/or natural IL-17A may be used to.
screen agents (e.g., other IL-17F signaling antagonists, e.g., anti-IL-17F
antibodies) that are capable of binding EL-17F and/or inhibiting IL-17F
bioactivity. Binding assays utilizing a desired binding protein, immobilized or
not, are well known in the art and may be used for this purpose with the
polypeptides related to the present invention, including the IL-17F signaling
antagonists of the invention, e.g., IL-17R and/or IL-17RC. Purified cell-based or
protein-based (cell-free) screening assays may be used to identify such agents.
For example, IL-17F protein may be immobilized in purified form on a carrier
and binding of potential ligands to purified IL-17F may be measured.
Antibodies
[0101] In other embodiments, the invention provides IL-17F signaling
antagonists as antibodies, i.e., intact antibodies and antigen binding fragments
thereof, that specifically bind to IL-17F (including IL-17F homodimers and/or
IL-17A/IL-17F heterodimers), preferably mammalian (e.g., human) IL-17F, or to

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the receptors for IL-17F, e.g., IL-17R and/or IL-17RC. In one embodiment, the
antibodies are inhibitory antibodies, i.e., they inhibit at least one IL-17F
bioactivity (e.g., binding of IL-17F and its receptor, IL-17F-mediated activation
of signaling components (e.g., NF-KB), IL-17F-mediated induction of cytokine
production, IL-17F-mediated increase in Aggrecanase etc.) and. may be useful in
diagnosing, prognosing, monitoring and/or treating disorders related to IL-17F
signaling. The upregulation of IL-17A and IL-17F production by IL-21 (see
Example 5) suggests that the proinflammatory effects associated with IL-21
binding to and activating IL-21R (e.g., IL-21 signaling) are mediated by IL-17A
homodirner, IL-17F homodimer, and/or IL-17A/IL-17F heterodimer.
Consequently, the antibodies of the invention that mitigate IL-17F signaling may
also be inhibitory antibodies to at least one activity associated with IL-21
signaling (e.g., modulation of cytokine production, inflammation in
inflammatory/autoirnmime disorders (such as inflammatory bowel disorders or
diseases (IBDs), rheumatoid arthritis, transplant/graft rejection, and psoriasis),
etc.; see U.S. Patent Application Nos. 60/599,086 and 60/639,176) and may be
useful in diagnosing, prognosing, monitoring and/or treating disorders associated
with IL-21 signaling.
[0102] Additionally, the invention provides anti-IL-17F antibodies that
specifically bind to but do not inhibit IL-17F signaling (i.e., detecting antibodies);
such antibodies may be used to detect the presence of IL-17F protein (e.g., as a
homodimer and/or heterodimer), e.g., as part of a kit for diagnosing, prognosing,
and/or monitoring a disorders) related to IL-17F signaling. In one embodiment,
the antibody is directed to IL-17F. In another embodiment, the antibody is a
monoclonal or single specificity antibody. The antibodies may also be human,
humanized, chimeric, or in vitro- generated antibodies against human IL-17F.
[0103] One of skill in the art will recognize that, as used herein, the term
"antibody" refers to a protein comprising at least one, and preferably two, heavy
(H) chain variable regions (abbreviated herein as VH), and at least one and
preferably two light (L) chain variable regions (abbreviated herein as VL). The
VH and VL regions can be further subdivided into regions of hypervariability,
termed "complementarity determining regions" ("CDRs"), interspersed with

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regions that are more conserved, termed "framework regions" ("FR"). The extent
of the FRs and CDRs has been precisely defined (see, Kabat et al. (1991)
Sequences of Proteins of Lnmunological Interest, Fifth Edition, U.S. Department
of Health and Human Services, NEE Publication No. 91-3242; and Chothia et al.
(1987) J. Mol. Biol. 196:901-917, which are hereby incorporated by reference).
Each VH and VL is composed of three CDRs and four FRs, arranged from
amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2,
CDR2, FRS, CDR3, FR4.
[0104] The antibody may further include a heavy and light chain constant region
to thereby form a heavy and light immunoglobulin chain, respectively. In one
embodiment, the antibody is a tetramer of two heavy immunoglobulin chains and
two light immunoglobulin chains, wherein the heavy and light immunoglobulin
chains are interconnected, e.g., by disulfide bonds. The heavy chain constant
region is comprised of three domains, CHI, CH2 and CH3. The light chain
constant region is comprised of one domain, CL. The variable region of the
heavy and light chains contains a binding domain that interacts with an antigen.
The constant regions of the antibodies typically mediate the binding of the
antibody to host tissues or factors, including various cells of the immune system
(e.g., effector cells) and the first component (Clq) of the classical complement
system.
[0105] Immunoglobulin refers to a protein consisting of one or more
polypeptides substantially encoded by immunoglobulin genes. The recognized
human immunoglobulin genes include the kappa, lambda, alpha (IgAl and IgA2),
gamma (IgGl, IgG2, IgG3, IgG4), delta, epsilon and mu constant region genes,
as well as the myriad immunoglobulin variable region genes. Full-length
immunoglobulin "light chains" (about 25 Kd, or 214 amino acids) are encoded by
a variable region gene at the NH2-terminus (about 110 amino acids) and a kappa
or lambda constant region gene at the COOH-terminus. Full-length
immunoglobulin "heavy chains" (about 50 Kd, or 446 amino acids), are similarly
encoded by a variable region gene (about 116 amino acids) and one of the other
aforementioned constant region genes, e.g., gamma (encoding about 330 amino
acids). The immunoglobulin heavy chain constant region genes encode for the

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antibody class, i.e., isotype (e.g., IgM or IgGl). The antigen binding fragment of
an antibody (or simply "antibody portion," or "fragment"), as used herein, refers
to one or more fragments of a full-length antibody that retain the ability to
specifically bind to an antigen (e.g., CD3). Examples of binding fragments
encompassed within the term "antigen.binding fragment" of an antibody include,
but are not limited to. (i) an Fab fragment a monovalent fragment consisting of
the VL, VH, CL and CHI domains; (ii) an F(ab')2 fragment, a bivalent fragment
comprising two Fab fragments linked by a disulfide bridge at the hinge region;
(iii) an Fd fragment consisting of the VH and CHI domains; (iv) an Fv fragment
consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb
fragment, which consists of a VH domain; and (vi) an isolated complementarity
determining region (CDR). Furthermore, although the two domains of the Fv
fragment, VL and VH, are coded for by separate genes, they may be joined, using
recombinant methods, by a synthetic linker that enables them to be made as a
single protein chain in which the VL and VH regions pair to form monovalent
molecules (known as single chain Fv (scFv)). Such single chain antibodies are
also intended to be encompassed within the term "antigen binding fragment" of
an antibody. These antibody fragments are obtained using conventional
techniques known to those skilled in the art, and the fragments are screened for
utility in the same manner as are intact antibodies.
[0106] Antibody molecules to the polypeptides of the present invention, e.g.,
antibodies to IL-17F protein, IL-17R, and/or IL-17RC, may be produced by
methods well known to those skilled in the art. For example, monoclonal
antibodies may be produced by generation of hybridomas in accordance with
known methods. Hybridomas formed in this manner are then screened using
standard methods, such as an enzyme-linked immunosorbent assay (ELISA), to
identify one or more hybridomas that produce an antibody that specifically binds
with the polypeptides of the present invention. For example, EL-17F proteins of
the invention may also be used to immunize animals to obtain polyclonal and
monoclonal antibodies that react with the IL-17F protein and which may inhibit
binding of IL-17F (e.g., EL-17F homodimer and/or IL-17A/IL-17F heterodimer)
to its receptor, e.g., EL-17R or IL-17RC. Similarly, IL-17R or IL-17RC proteins

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may be used to obtain polyclonal and monoclonal antibodies that specifically
react with IL-17R or EL-17RC, respectively, and which may inhibit binding of
these receptors to EL-17F protein specifically (including IL-17F homodimer and
IL-17A/IL-17F heterodimer), i.e., these antibodies do not inhibit binding of either
or both of these receptors to other IL-17F family members, e.g., IL-17A
homodirner. The peptide irnmunogcns additionally may contain a cysteine
residue at the carboxyl terminus, and may be conjugated to a hapten such as
keyhole limpet hemocyanin (KLH). Additional peptide immunogens may be
generated by replacing tyrosine residues with sulfated tyrosirie residues. Methods
for synthesizing such peptides are well known in the art. A full-length
polypeptide of the present invention may be used as the immunogen, or,
alternatively, antigenic peptide fragments of the polypeptides may be used. An
antigenic peptide of a polypeptide of the present invention comprises at least 7
continuous arnino acid residues and encompasses an epitope such that an
antibody raised against the peptide forms a specific immune complex with the
polypeptide. Preferably, the antigenic peptide comprises at.least 10 ammo acid
residues, more preferably at least 15 amino acid residues, even more preferably at
least 20 amino acid residues, and most preferably at least 30 amino acid residues.
[0107] Monoclonal antibodies may be generated by other methods known to
those skilled in the art of recombinant DNA technology. As an alternative to
preparing monoclonal antibody-secreting hybridomas, a monoclonal antibody to
a polypeptide of the present invention may be identified and isolated by screening
a recombinant combinatorial inxtnunoglobulin library (e.g., an antibody phage
display library) with a polypeptide related to the present invention (e.g., IL-17F,
IL-17R, IL-17RC) to thereby isolate immunoglobulin library members that bind
to the polypeptides related to the present invention (e.g., IL-17F, IL-17R,
IL-17RC, respectively). Techniques and commercially available kits for
generating and screening phage display libraries are well known to those skilled
in the art. Additionally, examples of methods and reagents particularly amenable
for use in generating and screening antibody display libraries can be found in the
literature. For example, the "combinatorial antibody display" method is well
known and was developed to identify and isolate antibody fragments having a

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particular antigen specificity, and can be utilized to produce monoclonal
antibodies. After immunizing an animal with an hnmunogen as described above,
the antibody repertoire of the resulting B-cell pool is cloned. Methods are
generally known for obtaining the DNA sequence of the variable regions of a
diverse population of immunoglobulin molecules by using a mixture of oligomer
primers and PCR. For instance, mixed oligonucleotide primers corresponding to
the 5' leader (signal peptide) sequences and/or framework 1 (FR1) sequences, as
well as primers to a conserved 3' constant region, can be used for PCR
amplification of the heavy and light chain variable regions from a number of
murine antibodies; a similar strategy has also been used to amplify human heavy
and light chain variable regions from human antibodies.
[0108] Polyclonal sera and antibodies may be produced by immunizing a
suitable subject with a polypeptide of the present invention. The antibody titer in
the irniminized subject may be monitored over time by standard techniques, such
as with ELISA using immobilized protein. If desired, the antibody molecules
directed against a polypeptide of the present invention may be isolated from the
subject or culture media and further purified by well-known techniques, such as
protein A chromatography, to obtain an IgG fraction.
[0109] Fragments of antibodies to the polypeptides of the present invention may
be produced by cleavage of the antibodies in accordance with methods well
known in the art. For example, immunologically active Fab and F(ab')2
fragments may be generated by treating the antibodies with an enzyme such as
pepsin.
[0110] Additionally, chimeric; humanized, and single-chain antibodies to the
polypeptides of the present invention, comprising both human and nonhuman-
portions, may be produced using standard recombinant DNA techniques and/or a
recombinant combinatorial immunoglobulin library. Humanized antibodies may
also be produced using transgenic mice which are incapable of expressing
endogenous immunoglobulin heavy and light chain genes, but which can express
human heavy and light chain genes. For example, human monoclonal antibodies
(mAbs) directed against, e.g., IL-17F protein, may be generated using transgenic

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mice carrying the human imrnunoglobulin genes rather than murine
immunoglobulin genes. Splenocytes from these transgenic mice immunized with
the antigen of interest may then be used to produce hybridomas that secrete
human mAbs with specific affinities for epitopes from a human protein.
[0111] Chimeric antibodies, including chimeric immunoglobulin chains, maybe
produced by recombinant DNA techniques known in the art. For example, a gene
encoding the Fc constant region of a murine (or other species) monoclonal
antibody molecule is digested with restriction enzymes to remove the region
encoding the murine Fc, and tbe equivalent portion of a gene encoding a human
Fc constant region is substituted.
[0112] An antibody or an immunoglobulin chain may be humanized by methods
known in the art. Humanized antibodies, including humanized immunoglobulin
chains, may be generated by replacing sequences of the Fv variable region that
are not directly involved in antigen binding with equivalent sequences from
human Fv variable regions. General methods for generating humanized
antibodies are provided by Morrison (1985) Science 229:1202-07; Oi et al.
(1986) BioTechniques 4:214; Queen et al., U.S. Patent Nos. 5,585,089;
5,693,761; 5,693,762, the contents of all of which are hereby incorporated by
reference. Those methods include isolating, manipulating, and expressing the
nucleic acid sequences that encode all or part of immunoglobulin Fv variable
regions from at least one of a heavy or light chain. Sources of such nucleic acid
sequences are well known to those skilled in the art and, for example, may be
obtained from a hybridoma producing an antibody against a predetermined target.
The recombinant DNA encoding the humanized antibody, or fragment thereof,
then can be cloned into an appropriate expression vector.
[0113] Humanized or CDR-grafted antibody molecules or immunoglobulins may
be produced by CDR grafting or CDR substitution, wherein one, two, or all
CDRs of an immunoglobulin chain can be replaced. See, e.g., U.S. Patent No.
5,225,539; Jones et al. (1986) Nature 321:552-25; Verhoeyan et al. (1988)
Science 239:1534; Beidler et al. (1988) 1 Immunol. 141:4053-60; Winter, U.S.
Patent No. 5,225,539, the contents of all of which are hereby incorporated by

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reference. Winter describes a CDR-grafting method that may be used to prepare
the humanized antibodies of the present invention (UK Patent Application GB
2188638A; Winter, U.S. Patent No. 5,225,539), the contents of which are hereby
incorporated by reference. All of the CDRs of a particular human antibody may
be replaced with at least a portion of a nonhuman CDR, or only some of the
CDRs may be replaced with nonhuman CDRs, It is only necessary to replace the
number of CDRs required for binding of the humanized antibody to a
predetermined antigen.
[0114] Human antibodies may additionally be produced using transgenic
nonhuman animals that are modified so as to produce fully human antibodies
rather than the animal's endogenous antibodies in response to challenge by an
antigen. See, e.g., PCT publication WO 94/02602. The endogenous genes
encoding the heavy and light immunoglobulin chains in the nonhuman host have
been incapacitated, and active loci encoding human heavy and light chain
immunoglobulins are inserted into the host's genome. The human genes are
incorporated, for example, using yeast artificial chromosomes containing the
requisite human DNA segments. An animal which provides all the desired
modifications is then obtained as progeny by crossbreeding intermediate
transgenic animals containing fewer than the full complement of the
modifications. The preferred embodiment of such a nonhuman animal is a
mouse, and is termed the XENOMOUSE™ as disclosed in PCT publications
WO 96/33735 and WO 96/34096. This animal produces B cells that secrete fully
human immunoglobulins. The antibodies can be obtained directly from the
animal after immunization with an irnmunogen of interest, as, for example, a
preparation of a polyclonal antibody, or alternatively from immortalized B cells
derived from the animal, such as hybridomas producing monoclonal antibodies.
Additionally, the genes encoding the immunoglobuh'ns with human variable
regions can be recovered and expressed to obtain the antibodies directly, or can
be further modified to obtain analogs of antibodies such as, for example, single
chain Fv molecules.
[0115] Monoclonal, chimeric and humanized antibodies that have been modified
by, e.g., deleting, adding, or substituting other portions of the antibody, e.g., the

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constant region, are also within the scope of the invention. As nonlimiting
examples, an antibody can be modified by deleting the constant region, by
replacing the constant region with another constant region, e.g., a constant region
meant to increase half-life, stability, or affinity of the antibody, or a constant
region from another species or antibody class, and by modifying one or more
amino acids in the constant region to alter, for example, the number of
glycosylation sites, effector cell function, Fc receptor (FcR) binding, complement
fixation, etc.
[0116] Methods for altering an antibody constant region are known in the art.
Antibodies with altered function, e.g., altered affinity for an effector ligand, such
as FcR on a cell, or the Cl component of complement, can be produced by
replacing at least one amino acid residue in the constant portion of the antibody
with a different residue (see, e.g., EP 388,151 Al, U.S. 5,624,821 and U.S.
5,6485260, the contents of all of which are hereby incorporated by reference).
Similar types of alterations to. the murine (or other species) immunoglobulin may
be applied to reduce or eliminate these functions, and are known in the art.
[0117] For example, it is possible to alter the affinity of an Fc region of an
antibody (e.g., an IgG, such as a human IgG) for an FcR (e.g., Fc gamma Rl), or
for Clq binding by replacing the specified residue(s) with a residue(s) having an
appropriate functionality on its side chain, or by introducing a charged functional
group, such as glutamate or aspartate, or an aromatic nonpolar residue such as
phenylalanine, tyrosine, tryptophan or alanine (see. e.g., U.S. 5.624,821).
[0118] Anti-IL-17F, anti-IL-17R, or anti-EL-17RC antibodies of the invention
may be useful for isolating, purifying, and/or detecting IL-17F protein (e.g., in
monomer, homodimer, or heterodimer formation), IL-17R, or IL-17RC
polypeptides, respectively, in supernatant, cellular lysate, or on the cell surface.
Antibodies disclosed in this invention may be. also used diagnostieally to monitor,
e.g., IL-17F protein levels, as part of a clinical testing procedure, or clinically to
target a therapeutic modulator to a cell or tissue comprising the antigen of the
antibody. For example, a therapeutic such as a small molecule, or other
therapeutic of the invention may be linked to an anti-IL-17F, anti-IL-17R, or anti-

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IL17RC antibody in order to target the therapeutic to the cell or tissue expressing
IL-17F, IL-17R, or IL-17RC, respectively. Antagonistic antibodies (preferably
monoclonal antibodies) that bind to IL-17F, IL-17R, or IL-17RC protein may
also be useful in the treatment of a disease(s) related to IL-17F signaling, and/or a
disease(s) associated with IL-21 signaling (e.g., IL-21 binding to and activation
of IL-21 R), due to the relationship between IL-21 and IL-17F production. Thus,
the present invention further provides compositions comprising an inhibitory
antibody that specifically binds to IL-17F (in monomeric andAsr dimerized
forms), IL-17R, or IL-17RC that decreases, limits, blocks, or otherwise reduces
IL-17F signaling. Similarly, anti-IL-17F, anti-IL-17R, or anti-IL-17RC
antibodies may be useful in isolating, purifying, detecting, and/or diagnostically
monitoring IL-17F, IL-17R, or IL-17RC, respectively, and/or clinically targeting
a therapeutic modulator to a cell or tissue comprising IL-17F, IL-17R, or
IL-17RC, respectively.
[0119] In addition to antibodies for use in the instant invention, antibody-based
molecules may also be employed to modulate the activity of IL-17F homodimers,
IL-17A homodimers, and/or IL-17F/IL-17A homodimers. Such antibody-based
molecules include small modular immunopharmaceutical (SMIP™) drugs
(Trubion Pharmaceuticals, Seattle, WA). SMIPs are single-chain polypeptides
composed of a binding domain for a cognate structure such as an antigen, a
counterreceptor or the like, a hinge-region polypeptide having either one or no
cysteine residues, and immunoglobulin CH2 and CH3 domains (see also
www.trubion.com). SMIPs exhibit the binding specificity and activity of
monoclonal antibodies, but are approximately one-third to one-half the size of
conventional therapeutic monoclonal antibodies, and have an extensive in vivo
half-life. SMIPs and their uses and applications are disclosed in, e.g., U.S.
Published Patent Appln. Nos. 2003/0118592,2003/0133939,2004/0058445,
2005/0136049, 2005/0175614,2005/0180970,2005/0186216,2005/0202012,
2005/0202023,2005/0202028,2005/0202534, and 2005/0238646, and related
patent family members thereof, all of which are hereby incorporated by reference
herein in their entireties.

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ScreeniBg Assays
[0120] The polynucleotides and polypeptides related to IL-17F signaling may be
used in screening assays to identity pharmacological agents or lead compounds
for agents that are capable of modulating the activity of IL-17F in a cell or
organism and are thereby potential regulators of inflammatory responses. For
example, samples containing IL-17F (either natural or recombinant) may be
contacted with one of a plurality of test compounds (either biological agents or
small organic molecules), and the biological activity of IL-17F in each of the
treated samples can be compared with the biological activity of IL-17F in
untreated samples or in samples contacted with different test compounds. Such
comparisons will determine whether any of the test compounds results in: 1) a
substantially decreased level of expression or biological activity of IL-17F,
thereby indicating an antagonist of IL-17F, or 2) a substantially increased level of
expression or biological activity of EL-17F, thereby indicating an agonist of
IL-17F. In one embodiment, the identification of test compounds capable of
modulating TL-17F activity is performed using high-throughput screening assays,
such as BIACORE® (Biacore International AB, Uppsala, Sweden), BRET
(bioluminescence resonance energy transfer), and FRET (fluorescence resonance
energy transfer) assays, as well as ELISA and cell-based assays.
Small Molecules
[0121] Decreased IL-17F activity (and/or at least one activity associated with
IL-21 binding to and activation of IL-21R) in an organism (or subject) afflicted
with (or at risk for) disorders related to IL-17F signaling (and/or disorders
associated with IL-21 binding to and activation of IL-21R), e.g., inflammatory
bowel disease, rheumatoid arthritis, transplant rejection, psoriasis, etc., or in a
cell from such an organism (or subject) involved in such disorders, may also be
achieved through the use of small molecules (usually organic small molecules)
that antagonize, i.e., inhibit the activity of, IL-17F. Novel antagonistic small
molecules may be identified by the screening methods described above and may
be used in the treatment methods of the present invention described herein.

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[0122] Conversely, increased IL-17F activity (and/or IL-21 associated activity)
in an organism (or subject) afflicted with (or at risk for) an immune deficiency,
e.g., neutropenia, or in a cell from such an organism (or subject) involved in such
a disorder, may also be achieved through the use. of small molecules (usually
organic small molecules) that agonize, i.e., enhance the activity of, IL-17F.
Novel agoristic small molecules may be identified by the screening methods
described above and may be used in the methods of treating immune deficiencies,
e.g., as described in U.S. Patent Nos. 5,707,829; 6,043,344; 6,074,849 and U.S.
Patent Application No. 10/102,080, all of which are incorporated by reference in
their entireties.
[0123] The term small molecule refers to compounds that are not
macromolecules (see, e.g., Karp (2000) Bioinformatics Ontology 16:269-85;
Verkman (2004) AJP-Cell Physiol. 286:465-74). Thus, small molecules are often
considered those compounds that are, e.g., less than one thousand daltons (e.g.,
Voet and Voet, Biochemistry, 2nd ed., ed. N. Rose, Wiley and Sons, New York,
14 (1995)). For example, Davis et al. (2005) Proc. Natl. Acad. Sci. USA
102:5981-86, use the phrase small molecule to indicate folates, methotrexate, and
neuropeptides, while Halpin and Harbury (2004) PLos Biology 2:1022-30, use
the phrase to indicate small molecule gene products, e.g., DNAs, RNAs and
peptides. Examples of natural small molecules include, but are not limited to,
cholesterols, neurotransmitters, and siRNAs; synthesized small molecules
include, but are not limited to, various chemicals listed in numerous
commercially available small molecule databases, e.g., FCD (Fine Chemicals
Database), SMID (Small Molecule Interaction Database), ChEBI (Chemical
Entities of Biological Interest), and CSD (Cambridge Structural Database) (see,
e.g., Alfarano et al. (2005) Nuc. Acids Res. Database Issue 33:D416-24).
Methods for Diagnosing, Prognosing, and Monitoring the Progress of Disorders
Related to IL-17F Signaling
[0124] It is well known in the art that immunological mechanisms studied in
animal models, particularly murine models, may be and often are, translatable to
the human immune system. As such, although many of the Examples disclosed
herein demonstrate the ability of IL-17F signaling antagonists to inhibit IL-17F

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bioactivities in animal models, in addition to human samples, the disclosed
methods for diagnosing, prognosing, and monitoring disorders related to IL-17F
signaling will be particularly useful for diagnosing, prognosing and monitoring
such disorders in humans.
[0125] The present invention provides methods for diagnosing, prognosing, and
monitoring the progress of disorders related to IL-17F signaling in a subject (e.g.,
that directly or indirectly involve increases in the bioactivity of IL-17F) by
detecting an upregulation of IL-17F activity, e.g., by detecting the upregulation of
IL-17F, including but not limited to the use of such methods in human subjects.
Due to the direct relationship between IL-21 and IL-17F, the invention also
provides methods for diagnosing, prognosing, and monitoring the progress of
disorders associated with IL-21 binding to and activation of IL-21R in a subject
(e.g., that directly or indirectly involve increases in the bioactivity of IL-21) by
detecting an upregulation of IL-17F activity, e.g., by detecting the upregulation of
IL-17F, including but not limited to the use of such methods in human subjects.
These methods may be performed by 'utilizing prepackaged diagnostic kits
comprising at least one of the group comprising an IL-17F, IL-17R, or IL-17RC
polynucleotide or fragments thereof, an IL-;17F, IL-17R, or IL-17RC polypeptide
or fragments thereof (including fusion proteins thereof), or antibodies to an
IL-17F, IL-17R, or IL-17RC polypeptide or derivatives thereof, or modulators of
IL-17F, IL-17R, or IL-17RC polynucleotides and/or polypeptides as described
herein, which may be conveniently used, for example, in a clinical setting. A
skilled artisan will recognize that other indirect methods may be used to confirm
the upregulation of, e.g., IL-17F, such as counting the number of immune cells,
e.g., neutrophils.
[0126] "Diagnostic" or "diagnosing" means identifying the presence or absence
of a pathologic condition. Diagnostic methods include detecting upregulation of
IL-17F signaling (and/or IL-21 signaling) by deterniining a test amount of the
gene products (e.g., rnRNA, cDNA, or polypeptide, including fragments thereof)
of IL-17F, IL-17R, and/or IL-17RC in a biological sample from a subject (human
or nonhuman mammal), and comparing the test amount with a normal amount or
range (i.e., an amount or range from an individual(s) known not to suffer from

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disorders related to EL-17F signaling). Although a particular diagnostic method
may not provide a definitive diagnosis of disorders related IL-17F signaling, it
suffices if the method provides a positive indication that aids in diagnosis.
[0127] The present invention also provides methods for prognosing such
disorders by detecting the upregulation of IL-17F activity, e.g., by detecting
upregulation of IL-17F. IL-17R, or EL-17RC. "Prognostic" or "prognosing"
means predicting the probable development and/or severity of a pathologic
condition. Prognostic methods include determining the test amount of a gene
product of IL-17F, IL-17R, or IL-17RC in a biological sample from a subject,
and. comparing the test amount to a prognostic amount or range (i.e., an amount
or range from individuals with varying severities of disorders related to IL-17F
signaling and/or disorders associated with IL-21 signaling) for the gene product
of IL-17F, IL-17R, or IL-17RC, respectively. Various amounts of the EL-17F,
IL-17R, or IL-17RC gene product in a test sample are consistent with certain
prognoses for disorders related to IL-17F signaling and/or disorders associated
with IL-21 signaling. The detection of an amount of IL-17F, IL-17R, or IL-17RC
gene product at a particular prognostic level provides a prognosis for the subject.
[0128] The present invention also provides methods for moiritoring the progress
or course of such disorders related to IL-17F signaling (and/or disorders
associated with IL-21 signaling) by detecting the upregulation of IL-17F activity,
e.g., by detecting upregulation of IL-17F, IL-17R, or IL-17RC. Monitoring
methods include determining the test amounts of a gene product of EL-17F,
IL-17R, or IL-17RC in biological samples taken from a subject at a first and
second time, and comparing the amounts. A change in amount of an IL-17F,
IL-17R, or IL-17RC gene product between the first and second times indicates a
change in the course of IL-17F signaling-related disorders (and/or IL-21
signaling-associated disorders), with a decrease in amount indicating remission of
such disorders, and an increase in amount indicating progression of such
disorders. Such monitoring assays are also useful for evaluating the efficacy of a
particular therapeutic intervention in patients being treated for autoimmune
disorders.

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[0129] Increased IL-17F signaling in methods outlined above may be detected in
a variety of biological samples, including bodily fluids (e.g., whole blood,
plasma, and urine), cells (e.g., whole cells, cell fractions, and cell extracts), and
other tissues. Biological samples also include sections of tissue, such as biopsies
and frozen sections taken for bistological purposes. Preferred biological samples
include blood, plasma, lymph, tissue biopsies, urine, CSF (cerebrospinal fluid),
synovial fluid, and BAL (bronchoalveolar lavage). It will be appreciated that
analysis of a biological sample need not necessarily require removal of cells or
tissue from the subject. For example, appropriately labeled agents that bind
IL-17F signaling gene products (e.g., antibodies, nucleic acids) can be
administered to a subject and visualized (when bound to the target) using
standard imaging technology (e.g., CAT, NMR (MRI), and PET).
[0130] In the diagnostic and prognostic assays of the present invention, the
IL-17F, IL-17R, or IL-17RC gene product is detected and quantified to yield a
test amount. The test amount is then compared with a normal amount or range.
An amount significantly above the normal amount or range is a positive sign in
the diagnosis of disorders related to IL-17F signaling (and/or disorders associated
with H/-21 binding to and activation of IL-21R). Particular methods of detection
and quantitation of IL-17F, IL-17R, or IL-17RC gene products are described
below.
[0131] Normal amounts or baseline levels of IL-17F, IL-17R, or IL-17RC gene
products may be determined for any particular sample type and population.
Generally, baseline (normal) levels of EL-17F, EL-17R, or IL-17RC protein or
mRNA are determined by measuring respective amounts of IL-17F, IL-17R, or
IL-17RC protein or mRNA in a biological sample type from normal (i.e., healthy)
subjects. Alternatively, normal values of IL-17F, IL-17R, or IL-17RC gene
products may be determined by measuring the amount in healthy cells or tissues
taken from the same subject from which the diseased (or possibly diseased) test
cells or tissues were taken. The amount of IL-17F, IL-17R, or IL-17RC gene
products (either the normal amount or the test amount) may be determined or
expressed on a per cell, per total protein, or per volume basis. To determine the
cell amount of a sample, one can measure the level of a constitutively expressed

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gene product or other gene product expressed at known levels in cells of the type
from which the biological sample was taken.
[0132] It will be appreciated that the assay methods of the present invention do
not necessarily require measurement of absolute values of IL-17F, IL-17R, or
IL-17RC gene products because relative values are sufficient for many
applications of these methods. It will also be appreciated that in addition to the
quantity or abundance of IL-17F, IL-17R, or IL-17RC gene products, variant or
abnormal IL-17F, IL-17R, or IL-17RC gene products or their expression patterns
(e.g., mutated transcripts, truncated polypeptides) may be identified by
comparison to normal gene products and expression patterns.
[0133] Whether the expression of a particular gene in two samples is
significantly similar or significantly different, e.g., significantly above or
significantly below a given level, depends on the gene itself and, inter alia, its
variability in expression between different individuals or different samples. It is
within the skill in the art to determine whether expression levels are significantly
similar or different. Factors such as genetic variation, e.g., in IL-17F and/or IL-
17A expression levels, between individuals, species, organs, tissues, or cells may
be taken into consideration (when and where necessary) when deterrnining
whether the level of expression, e.g., of IL-17F and/or IL-17A, between two
samples is significantly similar or significantly different, e.g., significantly above
a given level. As a result of the natural heterogeneity in gene expression between
individuals, species, organs, tissues, or cells, phrase such as "significantly
similar" or "significantly above" cannot be defined as a precise percentage or
value, but rather can be ascertained by one skilled in the art upon practicing the
invention.
[0134] The diagnostic, prognostic, and monitoring assays of the present
invention involve detecting and quantifying IL-17F, IL-17R, or IL-17RC gene
products in biological samples. IL-17F, IL-17R, or IL-17RC gene products
include mRNAs and polypeptides, and both can be measured using methods well
known to those skilled in the art.

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[0135] For example, rnRNA can be directly detected and quantified using
hybridization-based assays, such as Northern hybridization, in situ hybridization,
dot and slot blots, and oligonucleotide arrays. Hybridization-based assays refer
to assays in which a probe nucleic acid is hybridized to a target nucleic acid. In
some formats, the target, the probe, or both are. immobilized. The immobilized
nucleic acid may be DNA, RNA, or another oligonucleotide or polynucleotide,
and may comprise naturally or nonnaturally occurring nucleotides, nucleotide
analogs, or backbones. Methods of selecting nucleic acid probe sequences for
use in the present invention are based on the nucleic acid sequence of IL-17F,
IL-17R, or IL-17RC and are well known in the art.
[0136] Alternatively, mRNA can be amplified before detection and quantitation.
Such amplification-based assays are well known in the art and include
polymerase chain reaction (PCR), reverse-transcription-PCR (RT-PCR), PCR-
enzyme-linked immunosorbent assay (PCR-ELIS A), and ligase chain reaction
(LCR). Primers and probes for producing and detecting amplified IL-17F,
IL-17R, or IL-17RC gene products (e.g., mRNA or cDNA) may be readily
designed and produced without undue experimentation by those of skill in the art
based on the nucleic acid sequences of IL-17F, JL-17R, or IL-17RC, respectively.
As a nonlimiting example, amplified IL-17F gene products may be directly
analyzed, for example, by gel electrophoresis; by hybridization to a probe nucleic
acid; by sequencing; by detection of a fluorescent, phosphorescent, or radioactive
signal; or by any of a variety of well-known methods, hi addition, methods are
known to those of skill in the art for increasing the signal produced by
amplification of target nucleic acid sequences. One of skill in the art will
recognize that whichever amplification method is used, a variety of quantitative
methods known in the art (e.g., quantitative PCR) may be used if quantitation of
gene products is desired.
[0137] IL-17F, IL-17R, or IL-17RC polypeptides (or fragments thereof) may be
detected using various well-known immunoiogical assays employing the
respective anti-IL-17F, anti-IL-17R, or anti-IL-17RC antibodies that may be
generated as described above. Immunoiogical assays refer to assays that utilize
an antibody (e.g., polyclonal, monoclonal, chirneric, humanized, scFv, and/or

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fragments thereof) that specifically binds to, e.g., an IL-17F polypeptide (or a
fragment thereof). Such well-known irnmunological assays suitable for the
practice of the present invention include ELISA, radioimmunoassay (RIA),
immunoprecipitation, immunofluorescence, fluorescence-activated cell sorting
(FACS), and Western blotting. An IL-17F polypeptide may also be detected
using a labeled IL-17R and/or IL-17RC polypeptide(s). Conversely, IL-17R or
IL-17RC may be detected using a labeled IL-17F polypeptide.
[0138] One of skill, in the art will understand that the aforementioned methods
may be applied to disorders related to IL-17F signaling.
Uses of Molecules Related to IL-17F Signaling in. Therapy
[0139] The present inventors are the first to demonstrate, inter alia, the
following: 1) binding of IL-17R and/or IL-17RC by IL-17F, or other IL-17F
agonists, is correlated with increased neutrophil infiltration, cartilage destruction,
etc.; 2) antibodies directed toward IL-17F may be used to detect IL-17F protein
and to inhibit at least one IL-17F bioactivity; 3) siRNAs directed to IL-17R and
IL-17RC may be used to decrease IL-17A and IL-17F bioactivity; 4) IL-17F
protein may form an IL-17F homodimer and an IL-17A/IL-17F heterodimer, and
thus, inhibitory antibodies directed toward IL-17F may also inhibit IL-17A
bioactivity that is mediated by IL-17A/IL-17F heterodimers; 5) IL-21 acts
synergistically with CD28 to upregulate TL-17A homodimers, EL-17F
homodimers, and IL-17A/IL-17F heterodimers, and thus antibodies that inhibit
IL-17F activity (e.g., IL-17F homodimer activity and/or IL-17A/IL-17F
heterodimer activity) may regulate IL-21 signal; 6) natural and recombinant
IL-17A homodimers, IL-17F homodimers, and IL-17A/IL-17F heterodimers may
be isolated and purified; 7) IL-17F heterodimers possess IL-17F bioactivity; 8)
antibodies against human IL-17F cross react with and partially neutralize primate
IL-17F; and 9) both IL-17F and IL-17A are increased in lesional tissues from
human patients with psoriasis and involved tissues in human patients with
Crohn's disease and ulcerative colitis. Although some animal models have been
used to identify some of the above correlations, it is well known in the art that
immunological mechanisms studied in animal models may be, and often are,
translatable to the human immune system. Additionally, the antibodies of the

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invention were used to isolate natural IL-17F in its homodimeric and
heterodimeric forms from primary human T cells, while the experiments
involving IL-17F regulation of Aggrecanase and profiling the expression levels
of IL-17A and IL-17F in psoriatic lesions and involved tissues in inflammatory
bowel disease were undertaken in human cells and tissues. As such, the disclosed
methods for using molecules related to IL-17F signaling, e.g., IL-17F agonists or
IL-17F signaling antagonists, to treat disorders related to IL-17F signaling and/or
disorders associated with IL-21 signaling, will he particularly useful for treating
such disorders in humans.
[0140] The IL-17F signaling-related molecules disclosed herein, including
modulators of IL-17F, IL-17R, or IL-17RC polynucleotide and/or polypeptide
activity identified using the methods described above, may be used in vitro, ex
vivo, or incorporated into pharmaceutical compositions and administered to
individuals in vivo to treat, for example, disorders related to IL-17F signaling
and/or IL-21 signaling, by administration of an IL-17F signaling antagonist (e.g.,
IL-17F, IL-17R, and/or IL-17RC inhibitory polynucleotides; soluble IL-17R
and/or IL-17RC polypeptides (including fragments and/or fusion proteins
thereof); inhibitory anti-IL-17F, anti-IL-17R, or anti-IL-17RC antibodies; and/or
antagonistic small molecules, etc.). Several pharmacogenomic approaches to be
considered in determining whether to administer IL-17F signaling-related
molecules are well known to one of skill in the art and include genome-wide
association, candidate gene approach, and gene expression profiling. A
pharmaceutical composition of the invention is formulated to be compatible with
its intended route of administration (e.g., oral compositions generally include an
inert diluent or an edible carrier). Other nonlimiting examples of routes of
administration include parenteral (e.g., intravenous), intradermal, subcutaneous,
oral (e.g., inhalation), transdermal (topical), transmucosal, and rectal
administration. The pharmaceutical compositions compatible with each intended
route are well known in the art.
[0141] IL-17F agonists or IL-17F signaling antagonists may be used as
pharmaceutical compositions when combined with apharmaceutically acceptable
carrier. Such a composition may contain, in addition to an IL-17F signaling-

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related molecules (e.g., IL-17F agonists or IL-17F signaling antagonists) and
carrier, various diluents, fillers, salts, buffers, stabilizers, solubilizers, and other
materials well known in the art. The term "pharmaceutically acceptable" means a
nontoxic material that does not interfere with the effectiveness of the biological
activity of the active ingredient(s). The characteristics of the carrier will depend
on the route of administration.
[0142] The pharmaceutical composition of the invention may also contain
cytoMnes, lymphokines, or other hematopoietic factors such as M-CSF, GM-
CSF, IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12,
IL-14, IL-15, G-CSF, stem cell factor, and erythropoietin. The pharmaceutical
composition may also include anticytokine antibodies as described in more detail
below. The pharmaceutical composition may contain thrombolytic or
antithrombotic factors such as plasminogen activator and Factor VIII. The
pharmaceutical composition may further contain other anti-inflammatory agents
as described in more detail below. Such additional factors and/or agents may be
included in the pharmaceutical composition to produce a synergistic effect with
IL-17F agonists or IL-17F signaling antagonists, or to minimize side effects
caused by the IL-17F agonists or IL-17F signaling antagonists. Conversely
IL-17F agonists or IL-17F signaling antagonists may be included in formulations
of the particular cytokine, lymphokine, other hematopoietic factor, thrombolytic
or antithrombotic factor, or anti-inflammatory agent to minimize side effects of
the cytokine, lymphokine, other hematopoietic factor, thrombolytic or
antitiirombotic factor, or anti-inflammatory agent.
[0143] The pharmaceutical composition of the invention may be in the form of a
liposome in which IL-17F agonists or IL-17F signaling antagonists are combined,
in addition to other pharmaceutically acceptable carriers, with amphipathic agents
such as lipids that exist in aggregated form as micelles, insoluble monolayers,
liquid crystals, or lamellar layers in aqueous solution. Suitable lipids for
liposomal formulation include, without limitation, rnonoglycerides, diglycerides,
sulfatides, lysolecithin, phospholipids, saponin, bile acids, etc.

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[0144] As used herein, the term "tlierapeutically effective amount" means the
total amount of each active component of the pharmaceutical composition or
method that is sufficient to show a meaningful patient benefit, e.g., amelioration
of symptoms of, healing of, or increase in rate of healing of such conditions.
"When applied to an individual active ingredient, administered alone, the term
refers to that ingredient alone. "When applied to a. combination, the term refers to
combined amounts of the active ingredients that result in the therapeutic effect,
whether administered in combination, serially or simultaneously.
[0145] In practicing the method of treatment or use of the present invention, a
therapeutically effective amount of an IL-17F agonist or IL-17F signaling
antagonist is administered to a subject, e.g., a mammal (e.g., a human). An
IL-17F signaling-related molecule may be administered in accordance with the
method of the invention either alone or in combination with other therapies, such
as treatments employing cytokines, lymphokines or other hematopoietic factors,
or anti-inflammatory agents. When coadministered with one or more agents,
IL-17F signaling antagonists may be administered either simultaneously with the
second agent, or sequentially. If administered sequentially, the attending
physician will decide on the appropriate sequence of administering, e.g., an
IL-17R and/or IL-17RC polypeptide (or fusion protein thereof) and/or inhibiting
antibody in combination with other agents.
[0146] When a therapeutically effective amount of an IL-17F agonist or IL-17F
signaling antagonist is administered orally, the binding agent will.be in the form
of a tablet, capsule, powder, solution or elixir. When administered in tablet form,
the pharmaceutical composition of the invention may additionally contain a solid
carrier such as a gelatin or an adjuvant. The tablet, capsule, and powder contain
from about 5 to 95% binding agent, and preferably from about 25 to 90% binding
agent. When administered in liquid form, a liquid carrier such as water,
petroleum, oils of animal or plant origin such as peanut oil, mineral oil, soybean
oil, or sesame oil, or synthetic oils may be added. The liquid form of the
pharmaceutical composition may further contain physiological saline solution,
dextrose or other saccharide solution, or glycols such as ethylene glycol,
propylene glycol, or polyethylene glycol. When administered in liquid form, the

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pharmaceutical composition contains from about 0.5 to 90% by weight of the
binding agent, and preferably from about 1 to 50% by weight of the binding
agent.
[0147] When a therapeutically effective amount of an IL-17F agonist or IL-17F
signaling antagonist is administered by intravenous, cutaneous or subcutaneous
injection, the IL-17F agonist or IL-17F signaling antagonist will be in the form of
a pyrogen-free, parenterally acceptable aqueous solution. The preparation of
such parenterally acceptable protein solutions, having due regard to pH,
isotonicity, stability, and the like, is within the skill of those in the art. A
preferred pharmaceutical composition for intravenous, cutaneous, or
subcutaneous injection should contain, in addition to the IL-17F agonist or
IL-17F signaling antagonist, an isotonic vehicle such as sodium chloride
injection, Ringer's injection, dextrose injection, dextrose and sodium chloride
injection, lactated Ringer's injection, or other vehicle as known in the art. The
pharmaceutical composition of the present invention may also contain stabilizers,
preservatives, buffers, antioxidants, or other additive known to those of skill in
the art.
[0148] The amount of an IL-17F agonist or IL-17F signaling antagonist in the
pharmaceutical composition of the present invention will depend upon the nature
and severity of the condition being treated, and on the nature of prior treatments
that the patient has undergone. Ultimately, the attending physician will decide
the amount of IL-17F agonist or IL-17F signaling antagonist with which to treat
each individual patient. Initially, the attending physician will administer low
doses of IL-17F agonist or IL-17F signaling antagonist and observe the patient's
response. Larger doses of IL-17F agonist or IL-17F signaling antagonist may be
administered until the optimal therapeutic effect is obtained for the patient, and at
that point the dosage is not generally increased further. It is contemplated that
the various pharmaceutical compositions used to practice the method of the
present invention should contain about 0.1 p.g to about 100 mg of IL-17F agonist
or IL-17F signaling antagonist, e.g., IL-17R and/or IL-17RC (including fusion
proteins thereof), per kg body weight.

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[0149] The duration of intravenous (i.v.) therapy using a pharmaceutical
composition of the present invention will vary, depending on the severity of the
disease heing treated and the condition and potential idiosyncratic response of
each individual patient. It is contemplated that the duration of each application of
the IL-17F agonist or IL-17F signaling antagonist may be in the range of 12 to 24
hours of continuous i.v. administration. Also contemplated is subcutaneous (s.c.)
therapy using a pharmaceutical composition of the present invention.. These
therapies can be administered daily, weekly, or, more preferably, biweekly, or
monthly. It is also contemplated that where the EL-17F agonist or IL-17F
signaling antagonist is a small molecule (e.g., for oral delivery), the therapies
may be administered daily, twice a day, three times a day, etc. Ultimately the
attending physician will decide on the appropriate duration of i.v. or s.c. therapy,
or therapy with a small molecule, and the timing of administration of the therapy,
using the pharmaceutical composition of the present, invention.
[0150] The polynucleotides and proteins of the present invention are expected to
exhibit one or more of the uses or biological activities (including those associated
with assays cited herein) identified below. Uses or activities described for
proteins of the present invention may be provided by administration or use of
such proteins or by administration or use of polynucleotides encoding such
proteins (such as, for example, in gene therapies or vectors suitable for
introduction of DNA).
Uses of IL-17F Signaling Antagonists to Decrease Inflammation
[0151] In one aspect, the invention features a method of decreasing an
inflammatory response, e.g., due to IL-21 signaling. The method may comprise
contacting a population of cells with an IL-17F signaling antagonist (e.g., IL-17F,
IL-17R, and/or IL-17RC inhibitory polynucleotides; soluble TL-17R and/or
IL-17RC polypeptides (including fragments and/or fusion proteins thereof);
inhibitory anti-IL-17F, anti-IL-17R, or IL-17RC antibodies; and/or antagonistic
small molecules, etc.) in an amount sufficient to inhibit the IL-17F activity of the
cell or population. Antagonists to IL-17F signaling may also be administered to
subjects for whom suppression of IL-17F signaling (and/or IL-21 signaling) is
desired. These conditions include, but are not limited to, inflammatory disorders,

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e.g., autoimmune diseases (e.g., arthritis (including rheumatoid arthritis),
psoriasis, systemic lupus erythematosus, multiple sclerosis), respiratory diseases
(e.g., COPD, cystic fibrosis, asthma, allergy), transplant rejection (including solid
organ transplant rejection), and inflammatory bowel diseases (e.g., ulcerative
colitis, Crohn's disease).
[0152] These methods are based, at least in part, on the finding that interfering
with IL-17F signaling, e.g., by using an interfering anti-IL-17F antibody,
decreases IL-17F-associated inflammatory responses, e.g., cytokine production
by primary fibroblast-like synoviocytes (Example 4.2). Accordingly, IL-17F
signaling antagonists, i.e., molecules that inhibit IL-17F activity (e.g;, anti-
IL-17F antibodies) may be used to decrease inflammation in vivo, e.g., for
treating orpreventing disorders related to IL-17F signaling and/or disorders
related to IL-21 signaling.
[0153] The methods of using IL-17F signaling antagonists may also be used
inhibit IL-17F inflammatory activity and thus, can be used to treat or prevent a
variety of immune disorders. Nonlimiting examples of the disorders that can be
treated or prevented include, but are not limited to, transplant rejection,
autoimmune diseases (including, for example, diabetes mellitus, arthritis
(including rheumatoid arthritis, juvenile rheumatoid arthritis, osteoarthritis,
psoriatic arthritis, reactive arthritis), multiple sclerosis, encephalomyelitis,
myasthenia gravis, systemic lupus erythematosus (SLE), autoimmune thyroiditis,
dermatitis (including atopic dermatitis and eczematous dermatitis), Reiter's
syndrome, psoriasis, Sjögren's syndrome, Crohn's disease, aphthous ulcer, iritis,
conjunctivitis, keratoconjunctivitis, ulcerative colitis, spondyloarthropathy,
ankylosing spondylitis, intrinsic asthma, allergic asthma, cutaneous lupus
erythematosus, scleroderma, vaginitis, proctitis, drug eruptions, leprosy reversal
reactions, erythema nodo sum leprosum, autoimmune uveitis, allergic
encephalomyelitis, acute necrotizing hemorrhagic encephalopathy, idiopathic
bilateral progressive sensorineural hearing loss, aplastic anemia, pure red cell
anemia, idiopathic thrombocytopenia, polychondritis, Wegener's granulomatosis,
chronic actiove hepatitis, Stevens-Johnson syndrome, idiopathic sprue, lichen
planus, Graves' disease, sarcoidosis, primary biliary cirrhosis, uveitis posterior,

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and interstitial lung fibrosis), graft-versus-host disease, pulmonary exacerbation
(e.g., due to bacterial infection), and allergy, such as atopic allergy. Preferred
disorders that can be treated using methods which comprise the administration of
IL-17F signaling antagonists, e.g., an inhibitory IL-17F antibody, include, but are
not limited to, inflammatory disorders, e.g., autoimmune diseases (e.g., arthritis
(including rheumatoid arthritis), psoriasis, systemic lupus erythematosus,
multiple sclerosis), respiratory diseases (e.g., COPD, cystic fibrosis, asthma,
allergy), transplant rejection (including solid organ transplant rejection), and
inflammatory bowel diseases (e.g., ulcerative colitis, Crohn's disease).
[0154] Using IL-17F signaling antagonists (e.g., IL-17F, IL-17R, and/or
IL-17RC inhibitory polynucleotides; soluble IL-17R and/or IL-17RC
polypeptides (including fragments and/or fusion proteins thereof); inhibitory anti-
IL-17F, anti-IL-17R, or IL-17RC antibodies; and/or antagonistic small molecules,
etc.), it is possible to modulate immune responses in a number of ways.
Downregulation may be in the form of inhibiting or blocking an inflammatory
response already in progress, or may involve preventing the induction of an
inflammatory response.
[0155] In one embodiment, IL-17F signaling antegonists, including
pharmaceutical compositions thereof, are administered in combination therapy,
i.e., combined with other agents, e.g., therapeutic agents, that are useful for
treating pathological conditions or disorders, such as immune disorders and
inflammatory diseases. The term "in combination" in this context means that the
agents are given substantially contemporaneously, either simultaneously or
sequentially. If given sequentially, at the onset of administration of the second
compound, the first of the two compounds is preferably still detectable at
effective concentrations at the site of treatment.
[0156] For example, the combination therapy can include one or more IL-17F
signaling antagonists (e.g., IL-17F, IL-17R, and/or IL-17RC inhibitory
polynucleotides; soluble IL-17R and/or IL-17RC polypeptides (including
fragments and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or
IL-17RC antibodies; and/or antagonistic small molecules, etc.) coformulated

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with, and/or coadministered with, one or more additional therapeutic agents, e.g.,
one or more cytokine and growth factor inhibitors, immunosuppressants, anti-
inflammatory agents, metabolic inhibitors, enzyme inhibitors, and/or cytotoxic or
cytostatic agents, as described in more detail below. Furthermore, one or more
IL-17F signaling antagonists described herein may be used in combination with
two or more of the therapeutic agents described herein. Such combination
therapies may advantageously utilize lower dosages of the administered
therapeutic agents, thus avoiding possible toxicities or complications associated
with the various monotherapies. Moreover, the therapeutic agents disclosed
herein act on pathways that differ from the IL-17F receptor signaling pathway,
and thus are expected to enhance and/or synergize with the effects of the IL-17F
signaling antagonists.
[0157] Preferred therapeutic agents used in combination with an IL-17F
signaling antagonist are those agents that interfere at different stages in an
inflammatory response. la one embodiment, one or more IL-17F signaling
antagonists described herein may be cofonnulated with, and/or coadministered
with, one or more additional agents such as other cytokine or growth factor
antagonists (e.g., soluble receptors, peptide inhibitors, small molecules, ligand
fusions); or antibodies or antigen binding fragments thereof that bind to other
targets (e.g., antibodies that bind to other cytokines or growth factors, their
receptors, or other cell surface molecules); and anti-inflammatory cytokines or
agonists thereof. Nonlimiting examples of the agents that can be used in
combination with the IL-17F signaling antagonists described herein, include, but
are not limited to, antagonists of one or more interleukins (ILs) or their receptors,
e.g., antagonists of IL-1, IL-2, IL-6, IL-7, IL-8, IL-12, IL-13, EL-15, IL-16, IL-18,
EL-21 and IL-22; antagonists of cytokines or growth factors or their receptors,
such as rumor necrosis factor (TNF), LT, EMAP-II, GM-CSF, FGF and PDGF.
IL-17F signaling antagonists can also be combined with inhibitors of, e.g.,
antibodies to, cell surface molecules such as CD2, CD3, CD4, CD8, CD20 (e.g.,
the CD20 inhibitor rituximab (RITUXAN®)), CD25, CD28, CD30, CD40, CD45,
CD69, CD80 (B7.1), CD86 (B7.2), CD90, or their ligands, including CD154
(gp39 or CD40L), or LFA-l/ICAM-1 and VLA-4/VCAM-1 (Yusuf-Makagiansar

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et al. (2002) Med. Res. Rev. 22:146-67). Preferred antagonists that can be used in
combination with IL-17F signaling antagonists described herein include
antagonists of IL-1, IL-12, TNFa, IL-15, EL-18, and EL-22.
[0158] Examples of those agents include IBL-12 antagonists, such as chimeric,
humanized, human or in vzTro-generated antibodies (or antigen binding fragments
thereof) that bind to BL-12 (preferably human IL-12), e.g., the antibody disclosed
in WO 00/56772; IL-12 receptor inhibitors, e.g., antibodies to human IL-12
receptor, and soluble fragments of the IL-12 receptor, e.g., human IL-12 receptor.
Examples of IL-15 antagonists include antibodies (or antigen binding fragments
thereof) against IL-15 or its receptor, e.g., chimeric, humanized, human or in
vitro-generated antibodies to human IL-15 or its receptor, soluble fragments of
the IL-15 receptor, and EL-15-bmding proteins. Examples of IL-18 antagonists
include antibodies, e.g., chimeric, humanized, human or in v#ro-generated
antibodies (or antigen binding fragments thereof), to human IL-18, soluble.
fragments of the IL-18 receptor, and IL-18 binding proteins (CL-18BP).
Examples of IL-1 antagonists include Intcrlcukm-1 -converting enzyme (ICE)
inhibitors, such as Vx740, IL-1 antagonists, e.g., IL-1RA (anikinra, KINERET™,
Amgen), sELlRH (Immunex), and antj-IL-l receptor antibodies (or antigen
binding fragments thereof).
[0159] Examples of TNF antagonists include chimeric, humanized, human of in
vitro-generated antibodies (or antigen binding fragments thereof) to TNF (e.g.,
human TNFa), such as (HUMIRA™, D2E7, human TNFa antibody), CDP-
571/CDP-870/BAY-10-3356 (humanized anti-TNFa antibody;
Celltech/Pharmacia), cA2 (chimeric anti-TNFa antibody; REMICADE®,
Centocor); anti-TNF antibody fragments (e.g., CPD870); soluble fragments of the
TNF receptors, e.g., p55 or p75 human TNF receptors or derivatives thereof, e.g.,
75 kdTNFR-IgG (75 kD TNF receptor-IgG fusion protein, ENBREL™;
Immunex), p55 kdTNFR-IgG (55 kD TNF receptor-IgG fusion protein
(LENERCEPT®)); enzyme antagonists, e.g., TNFa converting enzyme (TACE)
inhibitors (e.g., an alpha-sulfonyl hydroxamic acid derivative, and N-
hydroxyformamide TACE inhibitor GW 3333, -005, or -022); and TNF-bp/s-
TNFR (soluble TNF binding protein). Preferred TNF antagonists are soluble

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fragments of the TNF receptors, e.g., p55 or p75 human TNF receptors or
derivatives thereof, e.g., 75 kdTNFR-IgG, and TNFa converting enzyme (TACE)
inhibitors.
[0160] In other embodiments, the IL-17F signaling antagonists described herein
may be administered in combination with one or more of the following: IL-13
antagonists, e.g., soluble IL-13 receptors (sIL-13) and/or antibodies against
IL-13; IL-2 antagonists, e.g., DAB 486-IL-2 and/or DAB 389-IL-2 (IL-2 fusion
proteins, Scragen), and/or antibodies to IL-2R, e.g., anti-Tac (humanized anti-
IL-2R, Protein Design Labs). Yet another combination includes IL-17F signaling
antagonists (e.g., IL-17F, IL-I7R, and/or IL-17RC inhibitory polynucleotides;
soluble IL-17R and/or IL-17RC polypeptides (including fragments and/or fusion
proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or IL-17RC antibodies;
and/or antagonistic small molecules, etc.), antagonistic small molecules, and/or
inhibitory antibodies in combination with nondepleting anti-CD4 inhibitors
(IDEC-CE9. I/SB 210396; nondepleting primatized anti-CD4 antibody;
IDEC/SmithKline). Yet other preferred combinations include antagonists of the
costimulatory pathway CD80 (B7.1) or CD86 (B7.2), including antibodies,
soluble receptors or antagonistic ligands; as well as p-selectin glycoprotein ligand
(PSGL), anti-inflammatory cytokines, e.g., IL-4 (DNAX/Schering); IL-10 (SCH
52000; recombinant IL-10 DNAX/Schering); IL-13 and TGF-P, and agonists
thereof (e.g., agonist antibodies).
[0161] In other embodiments, one or more IL-17F signaling antagonists can be
coformulated with, and/or coadministered with, one or more anti-inflammatory
drugs, immunosuppressants, or metabolic or enzymatic inhibitors. Nonlimiting
examples of the drugs or inhibitors that can be used in combination with the
IL-17F signaling antagonists (e.g., IL-17F, IL-17R, and/or IL-17RC inhibitory
polynucleotides; soluble IL-17R and/or IL-17RC polypeptides (including
fragments and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or
IL-17RC antibodies; and/or antagonistic small molecules, etc.) described herein,
include, but are not limited to, one or more of: nonsteroidal anti-inflammatory
drug(s) (NSAIDs), e.g., ibuprofen, tenidap, naproxen, meloxicam, piroxicam,

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diclofenac, and indomethacin; sulfasalazine; eorticosteroids such as prednisolone;
cytokine suppressive anti-inflammatory drug(s) (CSAIDs); inhibitors of
nucleotide biosynthesis, e.g., inhibitors of purine biosynthesis, folate antagonists
(e.g., methotrexate (N-[4-[[(2,4-diarnino-6-pteridinyl)methyl] methylamino]
benzoyl]-L-glutamic acid); and inhibitors of pyrimidine biosynthesis, e.g.,
dihydroorotate dehydrogenase (DHODH) inhibitors. Preferred therapeutic agents
for use in combination with IL-17F signaling antagonists include NSAIDs,
CSAIDs, (DHODH) inhibitors (e.g., leflunomide)7 and folate antagonists (e.g.,
methotrexate).
[0162] Examples of additional inhibitors include one or more of: corticosteroids
(oral, inhaled and local injection); immunosuppresants, e.g., cyclosporin,
tacrolimus (FK-506); and mTOR inhibitors, e.g., sirolimus (rapamycin -
RAPAMUNE™ or rapamycin derivatives, e.g., soluble rapamycin derivatives
(e.g., ester rapamycin derivatives, e.g., CCI-779); agents which interfere with
signaling by proinflamrnatoiy cytokines such as TNFa or IL-1 (e.g. IRAK, NIK,
IKK, p38 or MAP kinase inhibitors); COX2 inhibitors, e.g., celecoxib, rofecoxib,
and variants thereof; phosphodiesterase inhibitors, e.g., R973401
(phosphodiesterase Type IV inhibitor); phospholipase inhibitors, e.g., inhibitors
of cytosolic phospholipase 2 (cPLA2) (e.g., trifiuoromethyl ketone analogs);
inhibitors of vascular endothelial cell growtli factor or growth factor receptor,
e.g., VEGF inhibitor and/or VEGF-R inhibitor; and inhibitors of angiogenesis.
Preferred therapeutic agents for use in combination with IL-17F signaling
antagonists (e.g., IL-17F, IL-17R, and/or IL-17RC inhibitory polynucleotides;
soluble IL-17R and/or IL-17RC polypeptides (including fragments and/or fusion
proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or IL-17RC antibodies;
and/or antagonistic small molecules, etc.) are immunosuppresants, e.g.,
cyclosporin, tacrolimus (FK-506); mTOR inhibitors, e.g., sirolimus (rapamycin)
or rapamycin derivatives, e.g., soluble rapamycin derivatives (e.g., ester
rapamycin derivatives, e.g., CCI-779); COX2 inhibitors, e.g., celecoxib and
variants thereof; and phospholipase inhibitors, e.g., inhibitors of cytosolic
phospholipase 2 (cPLA2), e.g., trifluoromethyl ketone analogs.

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[0163] Additional examples of therapeutic agents that can be combined with an
IL-17F signaling antagonist include one or more of: 6-mercaptopurines (6-MP);
azathioprine sulphasalazine; mesalazine; olsalazine; chloroquine/
hydroxychloroquine (PLAQUENIL®); pencillamine; aurotbiornalate
(intramuscular and oral); azathioprine; colchicine; beta-2 adrenoreceptor agonists
(salbutamol, terbutaline, salmeteral); xanthines (theophylline, arnrnophylline);
cromoglycate; nedocromil; ketotifen; ipratropium and oxitropium;
mycophenolate mofetil; adenosine agonists; antithrombotic agents; complement
inhibitors; and adrencrgic agents.
[0164] The use of the IL-17F signaling antagonists disclosed herein in
combination with other therapeutic agents to treat or prevent specific disorders
related to EL-17F signaling is discussed in further detail below.
[0165] Nonlimiting examples of agents for treating or preventing arthritic
disorders (e.g., rheumatoid arthritis, inflammatory arthritis, rheumatoid arthritis,
juvenile rheumatoid arthritis, osteo arthritis and psoriatic arthritis), with which
IL-17F signaling antagonists maybe combined include one or more of the
following: EL-12 antagonists as described herein; NSAIDs; CSAIDs; TNFs, e.g.,
TNFa, antagonists as described herein; nondepleting anti-CD4 antibodies as
described herein; IL-2 antagonists as described herein; anti-inflammatory
cytoktnes, e.g., IL-4, IL-10, IL-13 and TGF, or agonists thereof; IL-1 or IL-1
receptor antagonists as described herein; phosphodiesterase inhibitors as
described herein; Cox-2 inhibitors as described herein; iloprost: methotrexate;
thalidomide and thalidomide-related drugs (e.g., Celgen); leflunomide; inhibitor
of plasminogen activation, e.g., tranexamic acid; cytokine inhibitor, e.g., T-614;
prostaglandin El; azathioprine; an inhibitor of interleukin-1 converting enzyme
(ICE); zap-70 and/or lck inhibitor (inhibitor of the tyrosine kinase zap-70 or Ick);
an inhibitor of vascular endothelial cell growth factor or vascular endothelial cell
growth factor receptor as described herein; an inhibitor of angiogenesis as
described herein; corticosteroid anti-inflammatory drugs (e.g., SB203580); TNF-
convertase inhibitors; IL-11; 3L-13; IL-17 inhibitors; gold; pemcillamine;
chloroquine; hydroxychloroquine; chlorambucil; cyclophosphamide;
cyclosporine; total lymphoid irradiation; antithymocyte globulin; CD5-toxins;

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orally administered peptides and collagen; lobenzarit disodiurn; cytokine
regulating agents (CRAs) HP228 and HP466 (Houghten Pharmaceuticals, Inc.);
ICAM-1 antisense phosphorothioate oligodeoxynucleotides (ISIS 2302; Isis
Pharmaceuticals, Inc.); soluble complement receptor 1 (TP10; T Cell Sciences,
Inc.); prednisone; orgotein; glycosaminoglycan polysulphate; minocycline
(MINOCIN®); anti-EL2R antibodies: marine and botanical lipids (fish and plant
seed fatty acids); auranofin; phenylbutazone; meclofenamic acid; flufenamic
acid; intravenous immune globulin; zileuton; mycophenolic acid (RS-61443);
tacrolimus (FK-506); sirolimus (rapamycin); amiprilose (therafectin); cladribine
(2-chlorodeoxyadenosine); and azaribine. Preferred combinations include one or
more IL-17F signaling antagonists (e.g., IL-17F, IL- 17R, and/or IL-17RC
inhibitory polynucleotides; soluble IL-17R and/or IL-17RC polypeptides
(including fragments and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-
IL-17R, or IL-17RC antibodies; and/or antagonistic small molecules, etc.) in
combination with methotrexate or leflunomide, and in moderate or severe
rheumatoid arthritis cases, cyclosporine.
[0166] Preferred examples of inhibitors to use in combination with IL-17F
signaling antagonists to treat arthritic disorders include TNF antagonists (e.g.,
chimeric, humanized, human or in vitro-generated antibodies, or antigen binding
fragments thereof, that bind to TNF; soluble fragments of a TNF receptor, e.g.,
p55 orp75 human TNF receptor or derivatives thereof, e.g., 75 kdTNFR-IgG (75
kD TNF receptor-IgG fusion protein,. ENBREL™), p55 kD TNF receptor-IgG
fusion protein; TNF enzyme antagonists, e.g., TNFa converting enzyme (TACE)
inhibitors); antagonists of IL-12, IL-15, IL-18, IL-22; T cell and B cell-depleting
agents (e.g., anti-CD4 or anti-CD22 antibodies); small molecule inhibitors, e.g.,
methotrexate and leflunomide; sirolimus (rapamycin) and analogs thereof, e.g.,
CCI-779; cox-2 and cPLA2 inhibitors; NSAIDs; p38 inhibitors, TPL-2, Mk-2 and
KFkb inliibitors; RAGE or soluble RAGE; r-seiectin or PSGL-I inhibitors (e.g.,
small molecule inhibitors, antibodies thereto, e.g., antibodies to P-selectin);
estrogen receptor beta (ERB) agonists or ERB-NFkb antagonists. Most preferred
additional therapeutic agents that can be coadministered and/or coformulated
with one or more IL-17F signaling antagonists (e.g., IL-17F, IL-17R, and/or

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IL-17RC inhibitory polynucleotides; soluble IL-17R and/or IL-17RC
polypeptides (including fragments and/or fusion proteins thereof); inhibitory anti-
IL-17F, anti-IL-17R, or 1L-17RC antibodies; and/or antagonistic small molecules,
etc.) include one or more of: a soluble fragment of a TNF receptor, e.g., p55 or
p75 human TNF receptor or derivatives thereof, e.g., 75 kdTNFR-IgG (75 kD
TNF receptor-IgG fusion protein, ENBREL™); methotrexate, lefiunomide, or a
sirolimus (rapamycin) or an analog thereof, e.g., CCI-779.
[0167] Nonlimiting examples of agents for treating or preventing multiple
sclerosis with which IL-17F signaling antagonists can be combined include the
following: interferons, e.g., interferon-alphala (e.g., AVONEX™; Biogen) and
interferon-lb (BETASERON™ Chiron/Berlex); Copolymer 1 (Cop-1;
COPAXONETM Teva Pharmaceutical Industries, Inc.); hyperbaric oxygen;
intravenous immunoglobulin; cladribine; TNF antagonists as described herein;
corticosteroids; prednisolone; methylprednisolone; azathioprine;
cyclophospharnide; cyclosporine; cyclosporine A, methotrexate; 4-
aminopyridine; and tizanidinc. Additional antagonists that can be used in
combination with IL-17F signaling antagonists include antibodies to or
antagonists of other human cytokines or growth factors, for example, TNF, LT,
IL-1, IL-2, IL-6, IL-7, IL-8, IL-12IL-15, EL-16, IL-18, EMAP-11, GM-CSF,
FGF, and PDGF. IL-17F signaling antagonists as described herein can be
combined with antibodies to cell surface molecules such as CD2, CD3, CD4,
CDS, CD25, CD28, CD30, CD40, CD45, CD69, CD80, CD86, CD90 or their
iigands. The IL-17F signaling antagonists may also be combined with agents,
such as methotrexate, cyclosporine, FK506, rapamycin, mycophenolate mofetil,
lefiunomide, NSAJDs, for example, ibuprofen, corticosteroids such as
prednisolone, phosphodiesterase inhibitors, adenosine agonists, antithrombotic
agents, complement inhibitors, adrenergic agents, agents which interfere with
signaling by proinflarnrnatory cytokines as described herein, IL-Ib converting
enzyme inhibitors (e.g., Vx740), anti-P7s, PSGL, TACE inhibitors, T-cell
signaling inhibitors such as kinase inhibitors, metalloproteinase inhibitors,
sulfasalazine, azathioprine, 6-mercaptopurines, angiotensin converting enzyme

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inhibitors, soluble cytokine receptors and derivatives thereof, as described herein,
and anti-inflammatory cytokines (e.g. IL-4, IL- 10, IL-13 and TGF).
[0168] Preferred examples of therapeutic agents for multiple sclerosis with
which the EL-17F signaling antagonists can be combined include interferon-p, for
example, IFN-la and IFNb; copaxone, corticosteroids, IL-1 inhibitors, TNF
inhibitors, antibodies to CD40 ligand and CD80, IL-12 antagonists.
[0169] Nonlimiting examples of agents for treating or preventing inflammatory
bowel disease (e.g., Crohn's disease, ulcerative colitis) with which aIL-17F
signaling antagonist (e.g., IL-17F, IL-17R, and/or IL-17RC inhibitory
polynucleotides; soluble EL-17R and/or IL-17RC polypeptides (including
fragments and/or fusion proteins thereof); inhibitory anti-IL-17F, anti-IL-17R, or
IL-17RC antibodies; and/or antagonistic small molecules, etc.) can be combined
include the following: budenoside; epidermal growth factor; corticosteroids;
cyclosporine; sulfasalazine; aminosaiicyiates; 6-rnercaptopurine; azathioprine; ,
mctronidazole; lipoxygenase inhibitors; mesalamine; olsalazine; balsalazide;
antioxidants; thromboxane inhibitors; EL-1 receptor antagonists; anti-IL-1
monoclonal antibodies; anti-IL-6 monoclonal antibodies; growth factors; elastase
inhibitors; pyridinyl-imidazole compounds'; TNF antagonists as described herein;
IL-4, IL-10, IL-13 and/or TGFJ3 cytokines or agonists thereof (e.g., agonist
antibodies); IL-11; glucuronide- or dextran-conjugated prodrugs ofprednisolone,
dexamethasone or budesonide; ICAM-1 antisense phosphorotbioate
oligodeoxynucleotides (ISIS 2302; Isis Pharmaceuticals, Inc.); soluble
complement receptor 1 (TP10; T Cell Sciences, Inc.); slow-release mesalazine;
methotrexate; antagonists of platelet activating factor (PAF); ciprofloxacin; and
lignocaine.
[0170] In one embodiment, an BL-17F signaling antagonist (e.g., IL-17F, IL-17R,
and/or IL-17RC inhibitory polynucleotides: soluble IL-17R and/or EL-17RC
polypeptides (including fragments and/or fusion proteins thereof); inhibitory anti-
IL-17F, anti-IL-17R, or IL-17RC antibodies; and/or antagonistic small molecules,
etc.) can be used in combination with one or more antibodies directed at other
targets involved in regulating immune responses, e.g., transplant rejection.

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Nonlimiting examples of agents for treating or preventing immune responses
with which an IL-17F signaling antagonist of the invention can be combined
include the following: antibodies against other cell surface molecules, including
but not limited to CD25 (interleukin-2 receptor-a), CD1 la (LFA-1), CD54
(ICAM-1), CD4, CD45, CD28/CTLA4 (CD80 (B7.1), e.g., CTLA4 Ig-
abatacept (ORENCIA®)), ICOSL, ICOS and/or CD86 (B7.2). In yet another
embodiment, an IL-17F signaling antagonist is used in combination with one or
more general immunosuppressive agents, such as cyclosporin A or FK506.
[0171] In other embodiments, IL-17F signaling antagonists (e.g., IL-17F,
XL-17R, and/or IL-17RC inhibitory polynucleotides; soluble IL-17R and/or
IL-17RC polypeptides (including fragments and/or fusion proteins thereof);
inhibitory anti-IL-17F, anti-IL-17R, or IL-17RC antibodies; and/or antagonistic
small molecules, etc.) are used as vaccine adjuvants against autoimmune
disorders, inflammatory diseases, etc. The combination of adjuvants for treatment
of these types of disorders are suitable for use in combination with a wide variety
of antigens from targeted self-antigens, i.e., autoantigens, involved in
autoimmunity, e.g., myelin basic protein; inflammatory self-antigens, e.g.,
amyloid peptide protein, or transplant antigens, e.g., alloantigens. The antigen
may comprise peptides or polypeptides derived from proteins, as well as
fragments of any of the following: saccharides, proteins, polynucleotides or
oligonucleotides, autoantigens, amyloid peptide protein, transplant antigens,
allergens, or other rnacrornolecular components. In some instances, more than
one antigen is included in the antigenic composition.
[0172] For example, desirable vaccines for moderating responses to allergens in
a vertebrate host, which contain the adjuvant combinations of this invention,
include those containing an allergen or fragment thereof. Examples of such
allergens are described in U.S. Patent No. 5,830,877 and published International
Patent Application No. WO 99/51259, which are hereby incorporated by
reference in their entireties, and include pollen, insect venoms, animal dander,
fungal spores and drugs (such as penicillin). The vaccines interfere with the
production of IgE antibodies, a known cause of allergic reactions. In another
example, desirable vaccines for preventing or treating disease characterized by

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ainyloid deposition in a vertebrate host, which contain the adjuvant combinations
of this invention, include those containing portions of amyloid peptide protein
(APP). This disease is referred to variously as Alzheimer's disease, amyloidosis
or amyloidogenic disease. Thus, the vaccines of this invention include the
adjuvant combinations of this invention plus Ap peptide, as well as fragments of
Ap peptide and antibodies to Ap peptide or fragments thereof.
[0173] Methods of: 1) downregulating antigen presenting cell function; and 2)
combination therapy for managing immunosuppression are well known in the art
(see, e.g., Xiao et al. (2003) BioDrugs 17:103-11; Kuwana (2002) Hum.
Immunol. 63:1156-63; Lu et al. (2002) Transplantation 73:S19-S22; Rifle et al.
(2002) Transplantation 73:S1-S2; Mancini et al. (2004) Crit. Care. Nurs. Q.
27:61-64).
[0174] Another aspect of the present invention accordingly relates to kits for
carrying out the administration ofTL-17F signaling antagonists (e.g., IL-17F,
IL-17R, and/or IL-17RC inhibitory polynucleotides; soluble IL-17R and/or
IL-17RC polypeptides (including fragments and/or fusion proteins thereof);
inhibitory anti-EL-17F, anti-IL-17R, or IL-17RC antibodies; and/or antagonistic
small molecules, etc.) with other therapeutic compounds. In one embodiment,
the kit comprises one or more binding agents formulated in a pharmaceutical
carrier, and at least one agent, e.g., therapeutic agent, formulated as appropriate,
in one or more separate pharmaceutical preparations.
[0175] The entire contents of all references, patents, and published patent
applications cited throughout this application are hereby incorporated by
reference herein.
EXAMPLES
[0176] The following Examples provide illustrative embodiments of the
invention and do not in anyway limit the invention. One of ordinary skill in the
art will recognize that numerous other embodiments are encompassed within the
scope of the invention.

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[0177] The Examples do not include detailed descriptions of conventional
methods, such methods employed in the construction of vectors, the insertion of
genes encoding the polypeptides into such vectors and plasmids, the introduction
of such vectors and plasmids into host cells, and the expression of polypeptides
from such vectors and plasmids in host cells. Such methods are well known to
those of ordinary skill in hte art.
Example 1: IL-17F-mediated inflammatory responses and implications in
inflamrnatory disorders, e.g., rheumatoid arthritis, inflammatory respiratory
disorders, and inflammatory bowel disease
Example 1.1: Human EL-17F administration in naive mice induces neutrophil
influx into the peritoneum
[0178] The observation that IL-17F treatment results in increased proteoglycan
breakdown and decreased proteoglycan synthesis by articular cartilage
(Hymowitz et al. (2001) EMBOJ. 20:5332-41) suggests a role for IL-17F
signaling in the development of inflammatory diseases of joint tissue. Indeed,
synovial fluid samples from patients with rheumatoid arthritis and osteoarthritis
show degradation of proteoglycans including, e.g.3 aggrecan, keratin, and
collagen (see, e.g., Witter et al. (1987) Arth. Rheum. 30:519-29 and Yagi et al.
(2005) J: Orthop. Res. 23(5):1128-38), and in vitro arthritis models mimic this
phenomenon by displaying matrix and proteoglycan degradation (Neidhart et al.
(2000) Arth. Rheum. 43:1719-28).
[0179] Additionally, the increased expression of IL-17F observed in BAL
samples isolated from patients suffering from asthma (Kawaguchi et al. (2002) J.
Immunol. 167:4430-35) and colon samples isolated from patients suffering from
inflammatory bowel diseases, e.g., ulcerative colitis or Crohn's disease (Gurney
et aL (2003) GTCBIO Conference: Cytokines and Beyond) suggests an additional
role for IL-17F signaling in inflammatory disorders of lung and bowel tissues.
To investigate the role of IL-17F signaling in inflammatory responses, nai've mice
were injected intraperitoneally with PBS (as a control) or 100 g human IL-17F
(SEQ ID NO:2). Hours after treatment, samples from peripheral blood (PB; 1,2,
4, 6, 8, and 10 h) and peritoneal cavities (PEC; 2,4, 6, 8, and 10 h) were taken,
and the absolute neutrophil count (ANC) in each sample was determined. The

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data in Table 2 reflects the ability of EL-17F to increase neutrophil counts in
blood and peritoneum. This effect may explain the neutrophilia seen in patients
suffering from rheumatoid arthritis and chronic obstructive pulmonary diseases
(COPD).
Table 2. Absolute neutrophil counts (ANC; mean + SEM) in peripheral blood (PB) and
peritoneal cavity (PEC) samples isolated from mice injected with PBS (n — 5) or IL-17F
(n = 5). Asterisk denotes a p-value <0.05 compared to control samples.

Example 1.2: IL-17F signaling plays a role in inflammatory joint disorders
[0180] To further assess the involvement of IL-17F signaling in inflammation,
particularly inflammatory responses implicated in joint diseases (e.g., arthritis),
the ability of IL-17F to activate a primary factor involved in the transcription of
inflammatory cytokines, i.e., NF-B, in primary chondrocytes was determined.
Primary human or porcine chondrocytes were infected (100 MOT) with
adenovirus expressing an NF-KB reporter gene system, which detects activation
of endogenous NF-KB (i.e., translocation of NF-KB from the cytoplasm to the
nucleus) by measuring the expression of a luciferase gene that is controlled by an
NF-KB-responsive promoter (ED Mercury Pathway Profiling systems, BD
Biosciences, Palo Alto, CA). After 48-72 hours, infected chondrocytes were
cultured with varying concentrations of IL-17A (SEQ ID NO:4) or IL-17F. After
four hours of incubation with IL-17A or IL-17F, cells were lysed in 25 ul lysis
buffer (Promega, Madison, WT) for 20 min at RT, and activation of NF-KB was
measured using an automated luminometer. The data show that IL-17F activated
NF-KB in primary human chondrocytes (Figure 1 A) and primary porcine

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chondrocytes (Figure 1B) in a dose-dependent manner. Finally, the amount of
IL-17F required to activate NF-KB to levels above background was similar to the
amount of IL-17A required to activate NF-KB to levels above background
(Figure 1A).
[0181] The ability of IL-17F to activate the cytokine transcription factor, NF-KB,
in primary chondrocytes suggests that the role IL-17F plays in inflammation of
joint tissue, e.g., during the development of arthritis, involves the induction of
inflammatory cytolcines. To test the effect of IL-17F on inflammatory cytokine
production by joint tissues, human fibroblast-like synoviocytes isolated from two
patients diagnosed with rheumatoid arthritis (RA) were plated to semi-confluence
in 24 well plates and cultured in the absence or presence of 150 ng/ml IL-17F.
Supernatants were collected at 48 h and cytokine production assessed using a
multiplex cytokine system (Pierce-Bio, Rockford, JL). As shown in Figure 2,
IL-17F induced the production of inflammatory cytokines such as IL-6 and IL-8,
and chemokines, such as MCP-1 and GRO-a, by human fibroblast-like
synoviocytes isolated from RA patients.
[0182] The ability of IL-17F to activate NF-KB in primary chondrocytes and
induce production of inflammatory cytokines and chemokines, particularly
chemokines involved in neutrophil'recruitment, by human fibroblast-like
synoviocytes from RA patients supports a role for IL-17F in mediating
inflammatory responses by joint tissue. These data, taken together with data
demonstrating increased IL-17F expression in the paws of mice suffering from
collagen induced arthritis compared to control animals (data not shown) and the
presence of neutrophils within degenerated articular cartilage and joint space
(data not shown), suggests that IL-17F mediates inflammatory joint diseases
(e.g., rheumatoid arthritis) by inducing cytokine and chemokine production,
which subsequently recruits, to the site of inflammation, immune cells (e.g.,
neutrophils) that cause damage to surrounding tissues.

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Example 1.3: Primary mouse lung fibroblasts respond to IL-17F by upregulating
production of inflammatory chemokines and cytokines
[0183] To test the role of IL-17F in the development of inflammatory respiratory
diseases, murine lung fibroblast (MIL) cells were grown to semi-confluence on
24 well plates and treated with IL-17F (50 ng/ml). Supernatants were collected at
48 h, and cytokine production was assessed using a multiplex cytokine system
(Pierce-Bio, Rockford, EL). Figure 3 shows that IL-17F induced the MFL
production of inflammatory cytokines, such as EL-6, and chemokines, such as JE
(CCL2) and KC. These results suggest IL-17F contributes to inflammatory
responses implicated in inflammatory disorders of the lung (e.g., COPD, asthma,
allergy, cystic fibrosis) by inducing the production of inflammatory cytokines and
leukocyte chemoattractants.
Example 2: Characterization of IL-17F receptors
Example 2.1: IL-17F binds to IL-17R and IL-17RC
[0184] As EL-17F shares the greatest homology with IL-17A within the IL-17
family, and as it has been suggested that IL-17A and IL-17F signal via the IL-17
receptor, the ability of IL-17F to bind to the receptor for IL-17A (i.e., EL-17R;
SEQ ID NO:6) was determined. The ability of IL-17F to bind to IL-17RC, an
IL-17 receptor whose ligand to date has not been identified, was also tested.
[0185] ELISA plates were incubated with 1.5 fig/ml human IL-17R-Ig (SEQ ID
NO:34) or 1.5 ng/ml human IL-17RC-Ig (SEQ ID NO:35) overnight. Plates were
washed with PBS/1%BSA and incubated with serial dilutions of biotin-
conjugated IL-17 A or biotin-conjugated IL-17F for 2 h at room temperature
(RT). After washing, saturating concentrations of avidin-horseradish peroxidase
(HRP) were added, and plates were incubated for an additional 1 h at RT.
Unbound avidin-HRP was washed using PBS/1% BSA, and the ELISA was
developed using TBM. Bound BL-17A or IL-17F was detected by measuring the
absorbance at 405 ran.
[0186] Figures 4A and 4B demonstrate binding of IL-17F to both IL-17R and
IL-17RC, respectively, with IL-17F having a greater affinity for IL-17R
compared to" its affinity for IL-17RC (EC50 value for IL-17R:IL-17F = 1.23

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g/ml; EC50 value for IL-17RC:3L-17F = 15 g/ml). However, although IL-17F
bound to IL-17R, its affinity for the receptor was lower than that of the affinity of
IL-17A forthe same receptor (EC50 values for IL-17R: IL-17F= 1.23 g/ml,
IL-17R:IL-17A = 0.35 ng/ml; Figure 4A).
Example 2.2: Anti-IL-17R antibody and IL-17RC-Ig fusion protein, but not
IL-17R-Ig fasion protein, block IL-17F activity
[0187] To further characterize IL-17F receptor binding, human fibroblast cells
(104 cells/well) were stimulated with 0.5 ng/ml IL-17A or 20 ng/ml IL-17F in the
presence of increasing concentrations of an IL-17R-Ig fusion protein, an
IL-17RC-Ig fusion protein or an anti-IL-17R antibody. After 24 h, the GRO-a
concentrations of collected supematants were determined using a commercially
available ELISA (R.&D, Minneapolis, MN). Concentrations of GRO-a were
determined based on a standard curve.
[0188] Figure 5 demonstrates increased GRO-a production by human fibroblast
cells when incubated with IL-17A (A) or IL-17F (B), and further corroborates the
findings of Example 1.2 (demonstrating increased inflammatory cytokine
production by human fibroblast-like synoviocytes cultured with IL-17F). Figure
5A additionally shows that all three receptor antagonists, i.e., IL-17R-Ig
(hl7R.Fc), IL-17RC-Ig (hl7RH2.Fc) and anti-IL-17R antibody (ahIL17R),
blocked the ability of IL-17A to induce GRO-a. These data suggest that IL-17A
binds.to and requires both IL-17R and IL-17RC receptors for IL-17A signaling.
In contrast, only the anti-IL-17R antibody and the IL-17RC-Ig fusion protein, and
not the IL-17R-Ig fusion protein, notably blocked IL-17F activity (Figure 5B).
The data presented in Figure 5B suggest that IL-17F binds to IL-17R (see Figure
4), but does not require this receptor for EL-17F-mediated signaling. Altogether
these data suggest IL-17A and IL-17F may use different receptors to mediate
their activity on human fibroblast cells.

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Example 3: Generation and characterization of anti-IL-17F antibodies
Example 3.1: Generation of anti-TL-17F antibodies
[0189] A group of five mice (Jackson Labs, Maine) were injected with 2 u.g of
cDNA encoding human IL-17F. Purified plasmid cDNA was precipitated onto
gold beads to a concentration of 1 fig cDNA/0.5 nag gold. The gold beads and
precipitated cDNA were delivered, monthly in two nonoverlapping shots,
intradermally in the abdomen of 11-week old female Balb/c mice using the
Helios charged gene. These animals were immunized every four weeks and
spleens removed at end of this period. Reirnnaunizations were performed using
purified IL-17F protein in addition to IL-17F cDNA. Spleens were processed to
obtain a lymphocyte suspension and the resulting suspension was fused with the
myeloma cell line 653/P3 using 50% (w/v) polyethylene glycol 1500 by an
established procedure (Oi and Herzenberg (1980) in Selected Methods in Cellular
Immunology, Mishel and Schigi, eds. W. J. Freeman Co., San Francisco, CA, p.
351). The fused cells were plated in 96-well rnicrotiter plates at a density of 2 x
105 cells/well, and after 24 hr were subjected to HAT selection. Hybridoma cells
secreting putative anti-IL-17F antibodies were identified by solid and solution
phase ELISA. Wells containing hybridoma positive for the above assays were
expanded, cloned by limiting dilution and cryopreserved. Isotypes of antibodies
were determined using solid phase ELISA. Purified human IL-17F-Ig was used
to coat 96-well microtiter plates and detected by different isotype-specific biotin-
conjugated goat anti-mouse IgG (Zymed. South San Francisco, CA).
Streptavidin conjugated with horseradish peroxidase (HRP) was added and
specifically bound enzyme measured using a colorimetric substrate.
Example 3.2: Some anti-IL-17F antibodies inhibit IL-17F binding to IL-17R
[0190] To assess the ability of the anti-IL-17F antibodies to block binding of
IL-17F to IL-17R, inhibition assays were performed by modifying the ELISA
described in Example 2.1. Briefly, serial dilutions of anti-IL-17F antibodies were
preincubated with 7 g/ml IL-17F for 1 h at RT. Each cytokine:antibody mixture
was then added to separate wells of an ELISA plate previously coated with 100
l/well of 1.5 g/ml IL-17R-Ig. The mixture was incubated in the wells for 1 h at

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RT. After washing the plate with PBS/1 % BSA, saturating concentrations of
avidin-HRP were added, and the plate was incubated for an additional 1 h at RT.
Unbound avidin-HRP was washed away using PBS/1% BSA. The assay was
developed using TMB. Figure 6 demonstrates that five out of six antibodies
tested, i.e., anti-IL-17F-01, anti-IL-17F-02, anti-IL-17F-06, anti-IL-17F-07, and
(albeit to a lesser degree) anti-IL-17F-05 were able to block binding of IL-17F to
IL-17R. In contrast, anti-IL-17F-03 antibody did not inhibit IL-17F binding to
IL-17R (Figure 6).
Example 3.3: Some anti-IL-17F antibodies inhibit IL-17F binding to IL-17RC
[0191] To assess the ability of anti-IL-17F antibodies to block binding of IL-17F
to IL-17RC, inhibition assays using the modified ELISA, as described above,
were performed using plates previously coated with 1.5 g/ml IL-17RC-Ig and
IL-17F at a concentration of 20 g/ml. Figure 7 demonstrates that two out of 6
antibodies tested (anti-IL-17F-01 and anti-IL-17F-07) were able to inhibit
binding of IL-17F to IL-17RC. In contrast anti-IL-17F-02, anti-IL-17F-03, anti-
IL-17F-05 and anti-IL-17F-06 antibodies did not inhibit IL-1.7F binding to
IL-17RC (Figure 7). Taking Figures 6 and 7 together, the data not only suggest
that anti-IL-I7F antibodies bind to distinct sites on IL-17F, but also that anti-
IL-17F-02, and anti-IL-17F-06 antibodies bind to and/or inhibit binding to a site
on IL-17F unique for the IL-17F:IL-17R interaction while anti-IL-17F-01 and
anti-IL-17F-07 antibodies bind to and/or inhibit binding to a site on IL-17F
shared between IL-17R and IL-17RC. Consequently, these six antibodies may be
used to define distinct sites, i.e., epitopes, on IL-17F.
Example 4: Anti-IL-17F antibodies inhibit IL-17F bioactivities
Example 4.1: Anti-IL-17F antibodies inhibit IL-17F-mediated cytokine
production
[0192] To determine whether any of the anti-IL-17F antibodies described in
Example 3 inhibit IL-17F bioactivity, human fibroblast cells (104 cells/well) were
stimulated with human 20 ng/ml IL-17F in the presence of increasing
concentrations of a control antibody (mlgGl) or antibodies to IL-17F, i.e., anti-
IL-17F-01, anti-IL-17F-02, anti-IL-17F-03, anti-IL-17F-05, anti-IL-17F-06, or

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anti-IL-17F-07. After 24 h, supernatants were collected and GRO-a
concentrations determined using commercially available ELISA. Concentrations
of GRO- produced were determined based on a standard curve.
[0193] Figure 8 demonstrates that anti-lL-17F-01, anti-IL-17F-02, and anti-
IL-17F-07 antibodies inhibited human IL-i7F-inediated GRO-a production by
human fibroblast cells. The results, presented in Figures 6, 7, and 8, suggest a
model whereby IL-17F signaling is initiated by IL-17F binding to IL-17R, which
results in the subsequent recruitment and required signaling through IL-17RC.
Example 4.2: Potential uses of anti-IL-17F antibodies in the treatment of
inflammatory disorders
[0194] To determine the potential of anti-IL-17F antibodies, in particular anti-
IL-17F-07 antibody, as a therapeutic in the treatment of disorders related to
IL-17F signaling (e.g., autoimmune diseases, respiratory diseases, inflammatory
bowel diseases, etc.), porcine primary chondrocytes infected with a NF-B
reporter vector were incubated for 48 h with 100 ng/ml IL-17A or 500 ng/ml
IL- 17F preincubated for 1 h at RT in the absence or presence of one of the
following: 20 g/ml IL-17R-Ig fusion protein (TL17R/Fc), 10 g/ml anti-
IL-17F-07 antibody (antiIL17F), or 10 g/ml control antibody (mouselgG).
Figure 9 demonstrates that while incubation of the IL-17R-Ig fusion protein
inhibited IL-17A-mediated activation of NF-KB, it had no effect on IL-17F-
mediated activation of NF-B. In contrast, anti-XL-17F-07 antibody was able to
inhibit IL-17F-mediated activation of NF-KB, but had no effect on IL-17A-
mediated activation of NF-KB (Figure 9).
[0195] To assess whether inhibited NF-KB activation in the presence of anti-
IL-17F antibodies correlated with inhibited cytokine production, human
fibroblast-like synoviocytes incubated with IL-17F, as described in Example 1.2,
were incubated with an isotype control antibody, anti-IL-17F-01 antibody, or
anti-IL-17F-07 antibody. Concentrations of IL-6, IL-8, or GRO-a were assessed
as described in Example 1.2. Figure 10 demonstrates that the ability of anti-
IL-17F antibodies to inhibit IL-17F activation of NF-KB correlated with a

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decreased production of IL-6, EL-8, and GRO-a by primary fibroblast-like
synoviocytes isolated from two patients with rheumatoid arthritis. These data
suggest that antagonists of IL-17F signaling, including, but not limited to,
inhibitory antibodies directed toward IL-17F, may be used to reduce
inflammatory responses. In particular, inhibitors of IL-17F may be used in the
treatment of inflammatory responses associated with disorders related to IL-17F
signaling, i.e., IL-17F-associated disorders.
Example 5: Antibodies directed toward IL-17F and IL-17A maybe used to detect
and purify recombinant and natural IL-17F homodimers, IL-17A homodimers,
and IL-17A/IL-17F heterodimers
Example 5.1: Detection of recombinant IL-17A7IL-17A, IL-17F/IL-17F and
IL-17A/EL-17F by ELISA
[0196] cDNAs encoding for human IL-17A, human IL-17F or both human
IL-17A and human IL-17F were used to modify 293 cells. Expression of these
cDNAs resulted in the production of 1L-17A/IL-17A, IL-17F/IL-17F or
IL-17A/IL-i7F aimers. The conditioned media derived from these cells, i.e., the
recombinant cytokines, and either commercially available antibodies or
antibodies as described above, were used to develop ELISA formats for the
detection of IL-17A protein, IL-17F protein, or IL-17A/IL-17F heterodimers. For
the detection of IL-17A protein, i.e., as an IL-17A homodimer or an
IL-17A/IL-17F heterodimer, anti-IL-17A antibody was used as a capture
antibody and biotin labeled anti-IL-17A antibody was used as the detection
antibody (both antibodies are available from R&D Systems, Minneapolis, MN).
For the detection of IL-17F protein, i.e., as an IL-17F homodimer or an
IL-17A/IL-17F heterodimer, anti-IL-17F-01 antibody (as described above) and
biotin-labeled anti-IL-17F-07 antibody (as described above) were used as capture
and detection antibodies, respectively. For the detection of IL-17A/IL-17F
heterodimers, an anti-IL-17A antibody (R&D Systems) was used as a capture
antibody and biotin labeled anti-IL-17F-07 antibody was used as a detection
antibody. The IL-17A and IL-17F antibodies are not cross-reactive (data not
shown).

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[0197] ELISAs were performed according to a well-known protocol. Briefly,
ELISA plates were incubated with 2 ug/ml of capture antibody overnight. The
plates were washed with PBS/1%BSA to remove excess capture antibody and
incubated with serial dilutions of the conditioned media, (i.e., recombinant
IL-17A/IL-17A, IL-17F/IL-17F, IL-17A/IL-17F cytokines) for 2 h at RT. After
washing unbound cytokine, 0.07-0.5 ug/rnl biotin-conjugated developing
antibody was added and plates were incubated for 2 h at RT. Plates were washed
to remove unbound developing antibody, saturating concentrations of avidin-
horseradish peroxidase (HRP) were added, and plates were incubated for 1 h at
RT. Unbound avidin-HRP was washed away using PBS/1% BSA. The assay
was developed using TBM.
[0198] Figure 11 demonstrates the detection of recombinant IL-17A and IL-17F
homodimers, as well as the detection of recombinant IL-17A/IL-17F
heterodimers. When capture and detection antibodies are both directed toward
one cytokine, (i.e., IL-17A or IL-17F), both homodimers and heterodimers of that
cytokine were detected (Figures 11A and 11B). In contrast, -when an anti-
IL-17A antibody and an anti-IL-17F antibody are used as capture and detection
antibodies, respectively, only IL-17A/IL-17F heterodimers are detected (Figure
11C). These data suggest that the IL-17A/IL-17F antibody pair may be used to
detect and potentially purify natural (i.e., nonrecombinant) IL-17A/IL-17F
heterodimers in conditioned media derived from primary cells. Additionally,
these results suggest that anti-IL-17F-07 antibodies, and likely anti-IL-17F-01
antibodies and other anti-I1-17F antibodies, as described herein, may also be
directed against IL-17A/IL-17F heterodimers.
Example 5.2: Detection of natural IL-17A homodimers, natural IL-17F
homodimers, and natural IL-17A/IL-17F heterodimers
[0199] Human CD4+ T cells (5 x 105 cells/ml) were activated with anti-CD3-
coupled beads (5 g/107 beads), and increasing concentrations of anti-CD28
antibodies (R&D, Minneapolis, MN), and in the absence or presence of IL-21 (60
ng/rnl) or IL-23 (0.5 ng/ml). Supernatants were collected 72 hours after primary
activation and the concentration of IL-17A or IL-17F was determined by ELISA
for IL-17A protein, or IL-17F protein, respectively, as described above

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(Example 5.1). Figure 12 demonstrates that IL-21 or 3GL-23 may be used to
enhance IL-17A or IL-17F production by T cells undergoing primary activation.
IL-2, IL-7, and IL-15 also induced IL-17A and IL-17F production upon
CD3/CD28 stimulation (data not shown).
[0200] Human CD4+ T cells (5 x 105 cells/ml) were activated with anti-CD3-
co-upled beads (5 g/10 beads) and soluble anti-CD28 antibodies for 48 hours.
Activated T cells were harvested, rested overnight, and reactivated in the
presence of bead-bound anti-CD3, anti-CD28 antibodies, IL-21 (60 ng/ml) or
IL-23 (0.5 ng/ml). Supematants were collected 72 hours after secondary
activation and production IL-17A or IL-17F was determined by ELISA for
IL-17A protein, or IL-17F protein, respectively, as described above. Figure 13
demonstrates that IL-21 or IL-23 synergizes with CD28 costimulation to enhance
IL-17A or IL-17F production by T cells undergoing secondary activation.
[0201] Human CD4+ T cells (2 x 106 cells/ml) were subjected to primary
activation with anti-CD3-coupled beads (5 p.g/107 beads) and soluble anti-CD28
antibody (0.5 g/ml). After 48 h of primary activation, conditioned media (CM1)
was collected and cells rested overnight. The next day, cells were counted and
restimulated at 2 x 106 cells/ml as described for the primary activation above and
in the presence of 60 ng/ml IL-21. After 72 h of restimulation, conditioned
media (CM2) was collected. The presence or absence of IL-17A homodimers,
IL-17F homodimers, and IL-17A/IL-17F heterodimers in neat and 1:10 diluted
CM1 and CM2 was assessed using the ELISA formats described in Example 5.1.
[0202] The data indicate little to no detection of IL-17A homodimers or
IL-17A/IL-17F heterodimers in CM1 media, i.e., media of T cells that underwent
primary activation (Figures 14A and 14C). In contrast, conditioned media of
restimulated T cells (CM2) comprised not only IL-17A and IL-17F homodimers
but also IL-17A/IL-17F heterodimers (Figures 14A, 14B, and 14C). These data
indicate that T cells, the "natural" source of IL-17 cytokines, express both
homodimers and heterodimers of IL-17A and IL-17F. These results also indicate
that antibodies directed against IL-17F can recognize and react with both IL-17F
homodimers and IL-17A/IL-17F heterodimers, and that such antibodies may be

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used to isolate and inhibit the biological activity of IL-17F homodimers and/or
IL-17ML-17F heterodimers.
Example 5.3: Immunoprecipitation of natural IL-17A homodimers, IL-17F
homodimers, and IL-17A/IL-17F heterodimers from T cells
[0203] Conditioned media (CM2) derived from T cells undergoing secondary-
activation in the presence of IL-21, as described in Example 5.2, was mixed wiih
20 g/ml murine anti-human IL-17A-02 (Wyeth) ormurine anti-human IL-17F-
01 (Wyeth) monoclonal antibodies for 1 h at 4°C under gentle rotation. Antibody
complexes from each mixture were separately immunoprecipitated with 50 ul
hydrated protein A-sepharose overnight at 4°C under gentle rotation. The
immunoprecipitated pellets were then sequentially washed with PBS/1% Tween
20, PBS/0.1% Tween 20, and PBS/0.05% Tween 20. The immunoprecipitated
pellets were resuspended in nonreducing sample buffer and loaded onto a 10%
Tricine gel for Western blot analysis with either anti-human IL-17A biotin
conjugation (R&D, Minneapolis,- MN) or rabbit anti-human IL-17F antibodies
(Wyeth).
[0204] IL-17F homodimers (35 kDa) were immunoprecipitated using murine
anti-human IL-17F-01 antibody and detected via Western blot analysis with a
rabbit anti-human IL-17F polyclonal antibody from 500 l of CM2. The IL-
17F/IL-17A heterodimers (32 kDa) were immunoprecipitated using murine anti-
human IL-17A-02 antibody and detected via Western blot analysis with a rabbit
anti-human IL-17F polyclonal antibody from 500 l of CM2 (Figure 15).
Neither the monoclonal nor the polyclonal antibody cross-reacted with IL-17A
(data not shown). Similarly, IL-17A homodimers (31 kDa) and IL-17F/A
heterodimers were immunoprecipitated using murine anti-human IL- 17A-02
antibody and detected via Western blot analysis using a polyclonal goat anti-IL-
17Abiotinylated antibody from 700 l of CM2. The IL-17F/IL-17A
heterodimers were immunoprecipitated using murine anti-human IL-17F-01
antibody and detected via Western blot analysis using a polyclonal goat anti-IL-
17A biotinylated antibody from 700 l of CM2 (Figure 16). The polyclonal
antibody cross-reacts with IL-17F homodimer at high protein concentrations
(data not shown).

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[0205] As controls (lane 2 of Figures 15 and 16), IL-17F homodimers were ,
purified from concentrated conditioned media overexpressing His tagged human
IL-17F. Briefly, concentrated conditioned media was' diluted 1:1 with 100 mM
Tris pH 8/1M NaCl/10 mM imidazole and loaded onto a Nickel-NTA Fast Flow
column (Qiagen, Valencia, CA). The homodimer was step eluted with 250 mM
iraidazole buffer. The protein was dialyzed against PBS-NSO. The homodimer
was then digested with EK (enterokinase) for 4 hours at room temp to remove the
Hiss tag. The digested protein was diluted 1:1 with 50 raM sodium phosphate pH
8/20 mM imidazole/300 mM NaCl and bound to a Nickel-NTA column (Qiagea.
Valencia, CA). The protein minus the tag was eluted with 40 rnM imidazole
buffer, and was dialyzed against PBS NSO. Purified IL-17A homodimers for use
as controls (lane 5 of Figure 15) were purchased from R&D Systems
(Minneapolis, MN).
Example 5.4: Immunoprecipitation of recombinant IL-17A homodimers, IL-17F
homodimers, and IL-17F/IL-17A heterodimers from transfected COS cells
[0206] Experiments were conducted to determine whether recombinant human
IL-17F and IL-17A would form heterodimers upon expression in COS cells, and
whether anti-IL-17F and anti-IL-17A antibodies were capable of
immunoprecipitating and detecting IL-17F/IL-17A heterodimers. COS cell
cultures were transfected with IL-17F cDNA, IL-17A cDNA, or both H-17F and
IL-17A cDNA, and the transfected cell cultures were allowed to secrete the
resultant protein(s) into the media. Conditioned media derived from either
expression of IL-17F or IL-17A or the coexpression of IL-17F and IL-17A was
mixed with 20 g/ml murine anti-human IL-17A-02 (Wyeth) or murine anti-
human IL-17F-01 (Wyeth) monoclonal antibodies for 1 hour at 4°C under gentle
rotation. Antibody complexes from each mixture were separately
immunoprecipitated with 50 ul-hydrated protein A-sepharose overnight at 4°C
under gentle rotation. The immunoprecipitated pellets were then sequentially
washed with PBS/1% Tween 20, PBS/0.1% Tween 20, and PBS/0.05% Tween
20. The immunoprecipitated pellets were resuspended in nonreducing sample
buffer and loaded onto a 10% Tricine gel for Western blot analysis with either

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goat anti-human IL-17A (R.&D, Minneapolis, MN) or rabbit anti-human IL-17F
antibodies (Wyeth).
[0207] IL-17F homodimers (35 kDa) and IL-17F/IL-17A heterodimers were
immunoprecipitated using murine anti-human IL-17F-01 antibody and detected
via Western blot analysis with a rabbit anti-human IL-17F polyclonal antibody
from 50 i of CM2 (Figure 17A; lanes 3 and 4, respectively). The IL-17F/IL-
17A heterodimers (32 kDa) were also irmnunoprecipitated using murine anti-
human IL-17A-02 antibody and detected via Western blot analysis with a rabbit
anti-human IL-17F polyclonal antibody from 50 1 of CM2 (Figure 17A; lane 9).
The IL-17A antibody used for immunoprecipitation in lanes 8-10 of Figure 17A
appeared to cross-react with IL-17F at high protein concentrations, since a band
corresponding to IL-17F homodimer is detected by the anti-IL-17F antibody
probe in lane 10. As shown in Figure 17B, the IL-17A homodimers (31 kDa)
and IL-17F/IL-17A heterodimers were immunoprecipitated using murine anti-
human IL-17A-02 antibody and detected via Western blot analysis using a
polyclonal goat anti-human IL-17A antibody from 50 l of CM2 (Figure 17B;
lanes 3 and 4, respectively). Also, the IL-17F/IL-17A heterodimers were
immunoprecipitated using murine anti-human IL-17F-01 antibody and detected
via Western blot analysis using a polyclonal goat anti-human IL-17A antibody
from 50 l of CM2 (Figure 17B; lane 6). As opposed to the IL-17A antibody
used for immunoprecipitation in Figure 17A, the IL-17F antibody used for
immunoprecipitation in lanes 5-7 of Figure 17B did not significantly cross-react
with IL-17A, since almost no band corresponding to IL-17A homodimer is
detected by the anti-IL-17A antibody probe in lane 5.
[0208] As controls (lanes 6-7 of Figure 17A), IL-17F homodimers were purified
as described in Example 5.3. Purified IL-17A homodimers for use as controls
(lane 5 of Figure 17A) were purchased from R&D Systems (Minneapolis, MN).
Control purified IL-17F homodimers migrate slightly faster than IL-17F
homodimers immunoprecipitated from conditioned media. This is likely due to
differences in glycosylation and/or the lack of an epitope tag on the IL-17F
proteins in the purified samples.

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Example 5.5: Purification of recombinant IL-17A/IL-17F heterodimers
[0209] Two methods of purifying IL-17ML-17F heterodimers are provided
herein. In the first method, COS cells were cotransfected with His6-tagged IL-
17F (SEQ ID NO:36) and raitagged IL-17A. Sodium chloride and imidazole
were added to the conditioned media to final concentrations of 500 mM and
6 mM, respectively. The conditioned media was then loaded onto a Nickel NTA
column (Qiagen, Valencia, CA). Thus, only IL-17F homodimer and IL-17F/IL-
I7A heterodimer, which contain a His tag, were captured on the nickel column.
The IL-17F homodimer and IL-17F/IL-17A heterodimer were then separated
with an imidazole gradient, and the IL-17F/IL-17A heterodimer was then
digested with EK to remove the His6 tag. The protein was dialyzed against PBS.
Edman sequencing was done to verify that the IL-17F and IL-17A protein was
detected in the IL-17F/A heterodimer sample. N-terminal sequence results
confirmed the existence of heterodimers, i.e., the first five amino acids for IL-17F
were shown to be RKIPK (SEQ ID NO:37), and for IL-17A were shown to be
IYKAG(SEQID NO:38).
[0210] The second method used a dual column purification scheme, which is
shown in the flow diagram set forth in Figure 18. Flag-tagged human IL-17A
(SEQ ID NO:39) and a His6-tagged human IL-17F (SEQ ID NO:36) were cloned
into separate pSMED2 vectors (Wyeth) and coexpressed in HEK293 cells by
lipofection. Briefly, cells were seeded in two 175-cm2 flasks 24 h prior to
transfection. For each flask, 24 jag pSMED2/Flag-IL-17A + 24 g
pSMED2/His6-IL-17F was mixed with 120 nl TRANSIT® reagent-LTl (Minis,
Madison, WI) in 2 ml serum-free media, and added to a flask containing cells
(90% confluent) and 25 ml DMEM media containing 10% heat-inactivated fetal
bovine serum. One day post-transfection, media was removed, the cells rinsed lx
with serum-free media, and fresh serum-free media was added (40 ml/flask).
Conditioned media was harvested 48 h later, filtered (0.45 ) to remove cells, and
frozen at —20°C. Protein expression was confirmed by Western analysis using
specific antibodies.

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[0211] The conditioned media was batch-bound to anti-Flag M2 affinity resin
(Sigma, St. Louis, MO) at 4°C for 2 hours. The bound proteins, IL-17A
homodimer and IL-17F/IL-17A heterodimer, were eluted using 50 mM Tris pH
8/500 mM NaCl/200 ng/ml Flag peptide (Sigma, St. Louis, MO). The flag
ehition was then batch-bound to Nickel-NT A resin (Qiagen, Valencia* CA)
overnight at 4°C. The bound protein, IL-17F/IL-17A hctcrodirncr, was eluted
using 50 mM Tris pH 8/1 M NaCl/500 mM imidazole.
[0212] Following purification of recombinant IL-17F/IL-17A heterodimers
substantially free from IL-17F and IL-17A homodimers, the activity of the
heterodimers was tested on BJ ceils by measuring the ability of the heterodimer
to stimulate GRO-a levels in the BJ cell culture media. Thus, BJ cultures were
stimulated with various concentrations of IL-17F homodimers, IL-17A
horriodrmers, or the purified recombinant IL-17F/IL-17A heterodimers. After
24 h, supernatants from the BJ cultures were collected and GRO-a concentrations
determined using commercially available ELISA. Briefly, BJ cells were seeded
at 5 x 103 cells/well in fiat-bottom 96-weii plates and supplied with 15 1 of
media containing IL-17A homodimers, IL-17F homodimers, or IL-17F/IL-17A
heterodimers. Piates were then incubated for 16-24 hours at 37°C, after which
the supernatants were removed and the concentration of GRO-a determined
using standard sandwich ELISA with antibodies to GRO-a (R & D Systems,
Minneapolis, MN). Concentrations of GRO-a produced were determined based
on a standard curve. The results are shown in Figure 19A. Similar to both JJL-
17F and EL-17A homodimers, the IL-17A/IL-17F heterodimer is capable of
stimulating IL-17 GRO-a concentrations in BJ cells. Moreover, as shown in
Figure 19B, treatment of BJ cultures with anti-JJL~17A antibodies, or anti-IL-17A
in combination with anti-JX-17F antibodies abrogated the ability of IL-17F/rL-
17A heterodimers to stimulate GRO-a levels.
Example 5.6: Mass spectrometry analysis of IL-17A homodimers, IL-17F
homodimers, and IL-17A/TL-17F heterodimers
[0213] To provide direct evidence of a disulfide linkage between two JX-17
monomers, the presence of disulfide linkages was verified and intermolecular

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disulfide-iinked peptides (IL-17A homodimers, IL-17F homodimers, and IL-
17A/IL-17F heterodimers) were identified by tandem mass spectrometric
analysis. Tryptic cleavage and reverse phase high performance liquid
chromatography (rpHPLC) were used to isolate disultlde-linked peptides, which
were then analyzed by nanoLC-MS/MS. Briefly, 1-2 g of purified, nonreduced
recombinani IL-I7A homodimer, IL-17F homodimer and IL-17A/IL-17F.
heterodimer were run on 10% Bis-Tris gels (Invitrogen, Carlsbad, CA), and
stained with the IMPERIAL Protein Stain Solution (Pierce, Rockford, IL).
Positively stained bands were excised and manually trypsin digested (Promega,
Madison, WT) for mass spectrometric analysis. For the digestion, the excised gel
slices were dehydrated in acetonitrile (ACN), rehydrated and washed in 25 mM
sodium phosphate buffer (pH 6.0), and dehydrated again in ACN. The protease
trypsin (0.5 (ig of trypsin dissolved in 25 mM sodium phosphate buffer) was
added, driven into the gel pieces by rehydration, and incubated for 4 h at 37°C.
The resulting peptides were further extracted from the gel with three successive
washes using aliquots of 60% ACN/1% formic acid (FA) and 90% ACN/5% FA,
These extracts were combined and evaporated, and the final sample reconstituted
in 2% ACN and 0.1% FA.
[0214] The digested samples were pressure-loaded onto a C18 PICOFRTT®
microcapillary column (New Objective, Woburn, MA) packed with Magic C18
beads (5 urn, 75 m x 11 cm, Michrom BioResources, Auburn, CA). The
column was then coupled to a linear ion trap mass spectrometer (LTQ,
ThermoFinnigan, San Jose, CA). The HPLC gradient increased linearly from 4-
60% ACN using Solvent B as a modifier (Solvent A, 2% ACN and 0.1% FA;
Solvent B, 90% ACN and 0.1% FA) over 70 min with a flow rate of 250 nl/min.
Mass spectra were collected using LTQ at tandem mass spectrometry mode
(referred to as MS/MS), in which each MS acquisition was followed by six
MS/MS acquisitions of the first six most intense peptide ions in the prior MS
spectrum. In some cases, MS/MS acquisitions were followed by two MS/MS/MS
acquisitions of the first two most intense peptide ions of the prior MS/MS
acquisitions. The peptide masses were recorded by scanning an m/z (mass-to-
charge ratio) range from 375 to 1500. The dynamic exclusion in the acquisition

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software provided by the manufacturer was also employed to increase the number
of peptide ions of interest to be analyzed. The MS/MS data were manually
interpreted.
[0215] At the MS level, the observed m/z of the peptide fragments
([M+3H]3+=919.7 for IL-17Ahomodimer; [M+3H]3+=1196.9 for IL-17F
homodimer; [M+3H]3+=1138.1 or 807.9 forIL-17F/IL-17Aheterodimer)
matched the calculated candidate disulfide-linked peptides. Further, the peptide
sequence according to the MS/MS data of these targeted masses was obtained,
and it was confirmed that they were the expected cysteine(C)-containing peptides
derived from IL-17A and/or IL-17F for the disulfide bond formation as shown in
Figure 20. In addition, MS3 data was acquired for the EL-17A homodimer
peptide ([M+3H]3+=907.7 and [M+3H]3+=843.3) due to the poor fragmentation at
the MS/MS level. This demonstrates that IL-17A homodimers, EL-17F
hornodimers, and IL-17F/IL-17A heterodimers exist as dimers via disulfide bond
linkage. In conclusion, the disulfide linkage patterns of the two homodimers and
the heterodimer were resolved, which were consistent to be Cl and C4 between
each monomer. Similar approaches were used in this study to demonstrate the
involvement of other cysteines (C2/C3 and C5/C6) for the intra-molecular
disulfide bond formation.
Example 6: Antibodies against human IL-17F inhibit primate IL-17F bioactivity
[0216] To determine whether the anti-fL-17F antibodies were capable of cross-
reacting with primate IL-17F, various concentrations of macaque IL-17F
conditioned media or purified human IL-17F were used to stimulate BJ cells in
the presence or absence of 100 p-g/ml anti-IL-17F-01 or anti-EL-17F-07
antibodies. Macaque IL-17F conditioned media for use in this experiment was
produced by expressing macaque IL-17F cDNA (SEQ ID NO:40) subcloned into
pCRII in HEK293 cells, and harvesting the conditioned media containing the
macaque IL-17F homodimers. After 16-24 hours of treatment with either human
or macaque IL-17F, the GRO-a concentrations of supernatants collected from the
treated cultures was determined using a commercially available ELISA (R&D,

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Minneapolis, MN) as described in Example 5.5. Concentrations of GRO-cc were
determined based on a standard curve.
[0217] Figure 21 demonstrates increased GRO-oc production by BJ cells
incubated with macaque IL-17F conditioned media or human IL-17F protein. As
described previously (see Figure 2 and Figure 8), human IL-17F stimulates
GRO-a levels, and this stimulation is inhibited by both anti-IL-17F-01 and anti-
IL-17F-07 antibodies (Figure 21A). As shown in Figure 21B, macaque IL-17F
also stimulates production of GRO-a in BJ cells. Both anti-IL-17F-01 and anti-
IL-17F-07 antibodies are capable of inhibiting the ability of macaque IL-17F
conditioned media to stimulate GRO-a cytokine levels. Thus, antagonist
antibodies to human IL-17F can cross-react with primate IL-17F to inhibit
primate IL-17F bioactivity.
Example 7: IL-17F stimulation of Aggrecanase 1 levels in human chondrocytes is
reduced by cotreatment with IL-17F antibodies
[0218] To determine whether IL-17F may be involved in the iiiflammatory
response accompanying, e.g., rheumatoid arthritis, nonarfhritic human cartilage
was obtained from National Disease Research Interchange (NDRI, Philadelphia,
PA.), and chondrocytes were isolated by serial enzymatic digestion of pronase
(1 mg/ml, 37°C for 30 min) and collagenase P (I mg/ml, 37°C overnight) within
48 hour postmortem. Upon isolation, cells were resuspended in Dulbecco's
modified Eagle's medium (DMEM)/F-12 media with 2 M L-glutamine, and
100U/ml penicillin/100 g/ml streptomycin containing 10% fetal bovine serum
(FBS). Cells were plated in 24-well plates at 1 x 106 cells/well. Media was
changed to serum-free media after 72 h and the chondrocytes were stimulated
with human IL-17F in the presence or absence of anti-IL-17F-07 or its isotype
control (IgG) for 6 h at 37°C. Cells were harvested immediately in RLT buffer
(Qiagen, Valencia, CA, RNBASY® Kit) with -mercaptoethanol and stored at
-80°C until ready for the RNA isolation. RNA was prepared using RNEASY®
Mini Kit, and DNase treatment was performed on the RNEASY® column for
15 min at room temperature as per the manufacturer's protocol. ADAMTS-4
(aggrecanase-1) mRNA expression levels were monitored by TAQMAN® PCR

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analysis (Applied Biosystems, Foster City, CA). Briefly, 100 ng of isolated RNA
was used for QPCR reaction with ADAMTS-4 probe/primers obtained from
Applied Biosystems. The expression of ADAMTS-4 was normalized to the
expression of GAPDH (10 ng of isolated RNA was used with GAPDH primers
obtained from Applied Biosystems) for each sample. A standard curve for '
sample- extrapolation was prepared using 0.16 ng to 100 ng of Universal
Reference Total RNA (Clontech, Palo Alto, CA) that consists of pools of
different tissues.
[0219] The results, presented as TAQMAN® units, are shown in Figure 22.
Thus, IL-17F treatment increases the expression of Aggrecanase 1 in human
chondrocytes, and treatment with. anti-IL-17F-07 antibodies abrogates this
stimulation. These data suggest that IL-17F involvement in inflammation and
joint degradation, such as occurs during autoimmune arthritis, e.g., reactive and
rheumatoid arthritis, may be mitigated by treatment with anti-IL-17F antibodies.
Example 8: Regulation of IL-17F and IL-17A bioactivity by siRNA knockdown
of receptors IL-17R and TL-17RC in BJ cells
[0220] Experiments were designed to determine whether a reduction in the level
of IL-17R and/or IL-17RC transcripts would reduce the bioactivity of IL-17F
and/or IL-17A. BJ cells were seeded 24 b prior to transfection in 96-well plates
at 9x103 cells/100 ul medium/well. Cells were transfected with chemically
synthesized RNAi reagents (Dharmacon,. Lafayette, CO) using
DHAKMAFECT® 1 (Dharmacon, Lafayette, CO) at 0.3 l/well, and individual or
pooled siRNAs at 10 nM or lower (see SEQ ID NOs:17-32). Following siRNA
transfection, the cells were incubated with transfection complexes for 18 h. The
transfection medium was then replaced by regular culture medium and incubated
for an additional 6 h. The regular culture medium was then replaced with 150 ul
of culture medium containing IL-17A at 1 ng/ml or IL-17F at 50 ng/ml.
Following 16 h of incubation with the designated cytokine, the culture
supernatants were collected for analysis by standard sandwich ELISA of the
ability of IL-17F and/or IL-17A to induce levels of IL-6, IL-8, and GRO-a (see

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Figure 2). Matched antibody pairs for hGRO-a, hIL-6 and hIL-8 were
purchased from R&D Systems (Minneapolis, MN).
[0221] To measure decreases in IL-17R and IL-17RC receptor levels following
siRNA treatment, the TURBOCAPTURE® mRNA kit (Qiagen, Valencia, CA)
was used to isolate mRNA from BJ fibroblast ceils according to manufacturer's
instructions. A one-step RT qPCR'MASTERMTX PLUS® (Eurogentec, San
Diego, CA) TAQMAN® (Applied Biosystems) protocol was used whereby 10 p.1
of mRNA per sample was used in 25 \i\ TAQMAN PCR reactions performed on
an ABI PRISM® 7700 DNA Sequence Detector (Applied Biosystems). The
conditions for TAQMAN® PCR were as follows: 30 min at 48°C, 10 min at
95°C, then 40 cycles each of 15 s at 95°C and 1 min at 60°C on MICRO AMP
OPTICAL® (Applied Biosystems) 96-well plates, covered with MICROAMP
OPTICAL® caps. Each plate contained triplicates of the test cDNA templates or
no-template controls for each reaction mix. The expression for each mouse gene
was normalized to human j32 microglobulin gene expression. The TAQMAN®
gene expression assay probe-primer sets for IL-17R and IL-17RC were acquired
from Applied Biosystems.
[0222] The results presented in Figure 23 depict the percent reduction hi GRO-a
levels (normalized to p2-microglobulin) following siRNA treatment of BJ
cultures. siRNA treatment of BJ cultures decreased BL-17R and IL-17RC
transcript levels by about 80% (Figure 23A and Figure 23B - "Taqman").
While decreases in both JL-17R and JJL-17RC levels reduced the ability of IL-
17A and EL-17F to stimulate GRO-a levels (Figure 23A and Figure 23B),
reduction in EL-17RC levels (Figure 23B) had a more pronounced effect than
reduction in JX-17R levels (Figure 23A) on both JX-17A and JX-17F bioactivity.
Interestingly, the reduction in JX-17RC had a greater effect on the ability of JX-
17A to stimulate GRO-a levels (Figure 23B). Preferred examples of siRNAs
that target IL-17R and JX-17RC are disclosed in Figure 23C (see also SEQ ID
NOs:17-32). These data suggest that both IL-17A and IL-17F can signal through
IL-17R and IL-17RC, and that IL-17RC may be a preferred receptor for both
molecules in relation to GRO- stimulation.

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Example 9:1L-17A and IL-17F are upregulated in afflicted tissues from human
patients with psoriasis, Crohn's disease, and ulcerative colitis
[0223] Psoriatic tissue hiopsy samples were collected from patients enrolled in
Wyeth-sponsored Clinical Study #3067K6-207 (A Randomized, Double-blind,
Placebo-controlled, Exploratory Pharmacogenomic Study of Recombinant
Human Interleukin Eleven, rhIL-11, in Patients with Active Psoriasis). Baseline
(visit 2) psoriatic lesional and nonlesional skin biopsies from 48 patients were
flash frozen in liquid nitrogen immediately after collection and shipped to the
Wyeth Clinical Pharmacogenomics Laboratory in Andover, MA.
[0224] Crohn's disease samples were collected from patients enrolled in Wyeth-
sponsored Clinical Study #3067K6-204 (A Multicenter, Randomized, Double-
blind, Placebo-controlled, Safety and Exploratory Pharmacogenomic Study of
Orally Administered Recombinant Human Interleukin Eleven (RhIL-11) for the
Treatment of Patients with Active Crohn's Disease), and ulcerative colitis
samples were collected from patients enrolled in Clinical Study #3067K5-l 14 (A
Muiticenter, Randomized, Double-blind, Placebo-controlled, Dose-escalating;
Safety and Exploratory Pharmacogenomic Study of Orally Administered
Recombinant Human Interleukin Eleven (RhIL-11) in Patients with Mild to
Moderate Left-sided Ulcerative Colitis). Baseline (visit 2) paired involved and
noninvolved tissue biopsies from #3067K6-204 patients (16 patients), and
baseline (visit 1) paired tissue biopsies from the same anatomical area of sigmoid
and left colon from #3067K5-l 14 patients (12 patients) were flash frozen in
liquid nitrogen immediately after collection and shipped to the Wyeth Clinical
Pharmacogenomics Laboratory in Andover, MA.
[0225] Tissue was homogenized using a polytron, RNA was isolated from the
supernatant of the lysate using RNEASY® Mini Kit (Qiagen, Valencia, CA), and
treated with DNase (Qiagen RNase-free DNase Kit). The DNase-treated RNA
preparation was further purified using a Phase Lock Gel column (Brinkman,
Westbury NY), phenol:chloroform:lAA (isoamyl alcohol) extracted (Ambion,
Austin, TX), and concentrated using an RNEASY® mini column.
SPECTRAMAX® (Molecular Devices, Sunnyvale, CA) was used to quantify
RNA, and RNA quality was assessed by Agilent Bioanalyzer gel (Model 2100;

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Agilent Technologies, Palo Alto, CA). Conversion of 2 |ig of total RNA from
the above preparations to cDNA was accomplished using the Applied Biosystems
High Capacity cDNA Archive Kit (Applied Biosystems) by following the
manufacturer's instructions. Plates containing completed reactions were stored at
temperatures of-20°C (short term) or-80°C (long term).
[0226] Applied Biosystem's Assays-on-Demand (AOD) gene-specific primer-
probe pairs are prevalidated, QC tested and optimized for use on any ABI
PRISM® sequence detection system (all from Applied Biosystems). According to
the manufacturer's AOD protocol, a master mix was prepared using TAQMAIN
Universal PCR Master Mix (Applied Biosystems) containing IL-17F or IL-17A
primers, and aliquoted into a 96-well plate for a final volume of 50 l/well.
Duplicate wells for serially diluted standards and cDNA samples (50 ng/well)
were assayed on an ABI PRISM® 7700 Sequence detector (Sequence Detector
Software vl.7) using universal thermal cycling conditions of 50°C for 2 min,
95°C for 10 min, 95°C for 15 s (40 cycles), and extension at 60°C for 1 min.
[0227] Relative quantification of RNA transcript levels of IL-17F and IL-17A
was performed following the manufacturer's guidelines described for the ABI
PPISM® 7700 Sequence Detection System (Applied Biosystems). Specifically,
standard curves were calculated for target standards and endogenous control,
input values determined for target and endogenous controls using standard
curves' slope and y-intercept, and target input values were normalized to
endogenous control. Fold-change in IL-17F and IL-17A expression was
calculated using the 50 ng standard as a calibrator, and relative concentration of
sample was obtained by multiplying fold-change by calibrator, then averaging.
[0228] To utilize the standard curve method, a tissue was empirically determined
to express the target gene using TAQMAN® AOD (Applied Biosystems). Total
RNA from over 10 candidate target-positive tissues was obtained from Wycth
(Cambridge/Andover) and outside vendors. Multiple 2 g aliquots from a single
RNA preparation were converted to cDNA (as described above), pooled, stored
as aliquots at-80°C, and assayed for expression of target gene by TAQMAN®
(Applied Biosystems). Cycle threshold (Ct) values of ≥35 were considered

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below the limits of detection. For standard curve development, the goal was to
achieve a Ct value between 18 and 25 for 100 ng of cDNA; this allowed for
appropriate standard curve dynamic range. Preparations of positive control tissue
meeting these requirements were used to generate the standard curve for each
assay. Standard curves consisted of two-fold serial dilutions of total cDNA from
100 ng/well to 1.5 ng/well. Standard curves were performed on each plate for
every assay and were used for sample quantification and assay performance
monitoring- Due to 96-well plate space constraints, standard curve dilution
points of 25 ng and 3 ng were omitted when running samples. Inter-plate % CV
was < 3% for psoriasis samples, and <5% for Crohn's disease and ulcerative
colitis samples.
[0229] Genes that are expressed at similar levels in all samples (i.e., treated and
untreated, lesional and nonlesional, etc.) were selected to serve as endogenous
controls in the relative standard curve method. From a list of candidate
endogenous controls, it was determined that the gene designated ZNF592
(GenBank Accession No. NM_014630) produced acceptable standard curves and
did not vary significantly in lesional and nonlesional tissues, and involved and
noninvolved tissues (p<0.05 for psoriasis and p<0.09 for Crohn's disease and
ulcerative colitis samples). All study samples were normalized to ZNF592 levels
in deterinining relative concentration values.
[0230] A paired Student's t-test (pairing lesional and nonlesional samples, or
involved and noninvolved tissues, from each patient) was used to assess the
significance of the association between IL-17F and IL-17A expression levels and
lesional (psoriasis) or inflammatory phenotype (Crohn's disease or ulcerative
colitis). Fold-changes for the psoriasis study were calculated by dividing lesional
relative concentration values by nonlesional relative concentration values. Fold-
changes for the Crohn's disease and ulcerative colitis (IBDs) studies were
obtained by dividing involved relative concentration values by noninvolved
relative concentration values. Summary fold-changes were calculated by
averaging fold-changes from all patients for EL-17F of IL-17A levels.

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[0231] The results of these studies are shown in- Figure 24 and Figure 25. As
shown in Figure 24, both IL-17F and IL-17A expression levels are significantly
increased in lesional tissues from afflicted patients, suggesting that IL-17F and
IL-17A are involved in psoriasis in vivo. As shown in Figure 25, both IL-17A
and IL-17F are increased in the involved tissues from patients afflicted with
Croon's disease, as well as those from patients afflicted with ulcerative colitis.
The considerable heterogeneity among patients with Crohn's disease and
ulcerative colitis, coupled with the relatively small sample size, mitigated against
identifying a statistically significant association of IL-17A and IL-17F with the
involved phenotype. However, clustering tools showed that both IL-17A and IL-
17F were well correlated with the involved phenotype in the Crohn's disease
sample set (r=0.65) (data not shown). These data suggest that elevated levels of
IL-17A and BL-17F in involved tissues may play a role in the inflammatory
conditions associated with IBDs in vivo.
Example 10: LN cells from ovalbumin immunized mice produce IL-17F
[0232] 8-week-old C57BL/6 mice were immunized in the flanks with 100 g
ovalbumin protein emulsified in complete Freund's adjuvant. Seven days later,
inguinal lymph nodes were harvested. Lymph nodes were dissociated and the
ceils were restimulated with 50 ng phorbol ester 12-tetradecanoylphorbol-13
acetate, 1 g/ml ionomycin, and 1 g/ml GOLGIPLUG™ for 12 hours. Cells
were then harvested, stained for surface CD4 using anti-mouse CD4 PerCP Cy5.5
(Pharmagen, San Diego, CA). Cells were fixed and permeabilized with
CYTOFLX/CYTOPERM™ (BD Biosciences, San. Diego, CA) after which cells
were stained with 4 }g/ml rat IgGl ALEXA FLUOR® 647 conjugate (Invitrogen,
Carlsbad, CA) or with 4 g/ml rat anti-IL-17F (clone 15-1) ALEXA FLUOR®
647 (Invitrogen, Carlsbad, CA) for 30 min. Cells were then washed twice
with PERM/WASH™ (BD Biosciences, San. Diego, CA), and analyzed using
FACSCALJBUR™ (BD Biosciences, San. Diego, CA). Rat anti-IL-17F (clone
15-1) ALEXA FLUOR® 647 (Invitrogen, Carlsbad, CA) was prepared using an
ALEXA FLUOR® 647 conjugation kit from Invitrogen. The results are shown in

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Figure 26. Thus, in vivo CD4+ T cells from the lymph nodes of ovalburnin-
imrnunized mice produce IL-17F protein.
Example 11: Conclusion and Discussion
[0233] Among several findings, these data indicate that IL-21 and IL-23 induced
IL-17A and IL-17F upon TCR/CD28 costimulation, and that IL-23 and IL-21
synergize with costimulation for IL-17A and IL-17F production. Both IL-23 and
IL-21 are equally effective in IL-17 induction. These data suggest that IL-17A,
and particularly IL-17F (since it is produced at 10-20 fold higher levels compared
to IL-17A) may mediate some of the proinfiammatory effects attributed to IL-21,
and that inhibition of IL-17F (either as an IL-17F homodimer or an EL-17F
heterodimer) may have similar therapeutic effects as blocking IL-21 signaling
(sec, e.g., U.S. Patent Application Nos. 60/599,086 and 60/639,176). The
similarities between the effects of IL-17F signaling and EL-21 signaling lead to a
strong conclusion that inhibition of IL-17F signaling may be as therapeutically
valuable as inhibiting IL-21 signaling. Additionally, the results show for the first
time that T cells express IL-17A/IL-17F heterodimers, as well as IL-17A and
IL-17F homodimers; the results also show that such cytokines may be isolated
and purified in their natural and recombinant forms. The data presented herein
also shows that anti-IL-17F antibodies, fusion proteins comprised of IL-17F, and
siRNA targeting IL-17R and IL-17RC reduce IL-17F bioactivity. Further, the
results show that IL-17F treatment increases Aggrecanase expression in human
chondrocytes, which can be reduced by anti-IL-17F antibodies, and that IL-17F
and IL-17A are elevated in psoriatic lesions and tissues involved in IBD from
human biopsies.
[0234] IL-17A and IL-17F are novel proinfiammatory cytokines produced by
activated T cells. These cytokines share a high degree of amino acid identity,
including conserved cysteines that exhibit structural features of a cysteine knot
motif. Both cytokines have been proposed to share receptor chains and exhibit
similar biological functions. Members of the IL-17 cytokine family have been
implicated in diseases mediated by abnormal immune responses such as
rheumatoid arthritis, inflammatory bowel disorders (IBDs) and asthma. Due to

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the similarities enumerated above, IL-17A and IL-17F produced by human T
cells upon activation were characterized. CD4+ T cells were activated with anti-
CD3 in the presence or absence of CD28 costimulation, 7-common cytokines
(IL-2, IL-4, IL-7, H-15, IL-21) or IL-23. Optimal production of IL-17A and
IL-17F required TCR as well as CD28 costimulation. Additionally, CD28 and
IL-21 act synergistically in 3L-17A and TL-17F production, suggesting IL-17A
and IL-17F may mediate proinflammatory effects attributed to IL-21 signaling.
Under all activating conditions, protein levels of IL-17F were 10-20 fold above
those obtained for IL-17A. Interestingly, in addition to EL-17A homodimers and
IL-17F homodimers, T ceils also produced IL-17A/IL-17F heterodimers. These
findings suggest that multiple forms of these cytokines are present in vivo, with
each form accounting for distinct biological functions, e.g., that the
IL-17A/IL-17F heterodimer may constitute a new cytokme target in the treatment
of inflammatory diseases.

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WHAT IS CLAIMED IS:
1. Amethod of screening fortest compounds capable of antagonizing IL-17F
signaling comprising the steps of:
contacting a sample containing IL-17F.and IL-17R with a compound; and
determining whether the interaction of IL-17F with IL-17R in the sample is
decreased relative to the interaction of IL-17F with IL-17R in a sample not
contacted with the compound,
whereby such a decrease in the interaction of IL-17F with IL-17R in the
sample contacted with the compound identifies the compound as one that inhibits
the interaction of IL-17F with IL-17R and is capable of antagonizing IL-17F
signaling.
2. A method of screening for test compounds capable of antagonizing IL-17F
signaling comprising the steps of:
contacting a sample containing IL-17F and IL-17RC with a compound; and
determining whether the interaction of IL-17F with IL-17RC in the sample
is decreased relative to the interaction of IL-17F with IL-17RC in a sample not
contacted with the compound,
whereby a decrease in the interaction of IL-17F with IL-17RC in the
sample contacted with the compound identifies the compound as one that inhibits
the interaction of IL-17F with IL-17RC and is capable of antagonizing IL-17F
signaling.
3. A method for diagnosing a disorder related to increased IL-17F signaling in
a subject comprising the steps of:
detecting a test amount of an IL-17F signaling gene product in a sample
from the subject: and
comparing the test amount with a normal amount of the same IL-17F
signaling gene product in a control sample,
whereby a test amount significantly above the normal amount provides a
positive indication in the diagnosis of a disorder related to increased IL-17F
signaling.

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4. The method of claim 3, wherein the disorder is selected from the group
consisting of autoimmune diseases, respiratory diseases, and inflammatory bowel
diseases.
5. The method of claim 4, wherein the IL-17F signaling gene product is an
IL-17F gene product.
6. The method of claim 4, wherein the IL-17F signaling gene product is an
IL-17R gene product.
7. The method of claim 4, wherein the IL-17F signaling gene product is an
IL-17RC gene product.
8. A method of treating a subject at risk for, or diagnosed with, a disorder
related to increased IL-17F signaling comprising administering to the subject a
therapeutically effective amount of an IL-17F signaling antagonist.
9. The method of claim 8, wherein the IL-17F signaling antagonist is selected
from the group consisting of IL-17F inhibitory polynucleotides, IL-17R inhibitory
polynucleotides, IL-17RC inhibitory polynucleotides, soluble polypeptides
comprising IL-17R or IL-17F binding fragments thereof, soluble polypeptides
comprising IL-17RC or IL-17F binding fragments thereof, inhibitory anti-IL-17F
antibodies, inhibitory anti-IL-l7R antibodies, inhibitory IL-17RC antibodies, and
antagonistic small molecules.
10. The method of claim 9, wherein the IL-17F signaling antagonist is an
IL-17R inhibitory polynucleotide.
11. The method of claim 9, wherein the IL-17F signaling antagonist is an
IL-17RC inhibitory polynucleotide.

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12. The method of claim 10, wherein the inhibitory polynucleotide is an siRNA
selected from the group consisting of the nucleotide sequences set forth in SEQ ID
NOs: 17-24.
13. The method of claim 11, wherein the inhibitory polynucleotide is an siRNA
selected from the group consisting of the rmcleotide sequences set forth in SEQ ID
NOs:25-32.
14. The method of claim 9, wherein the IL-17F signaling antagonist is a soluble
polypeptide comprising IL-17R or IL-17F binding fragments thereof.
15. The method of claim 9, wherein the IL-17F signaling antagonist is a soluble
polypeptide comprising IL-17RC or EL-17F binding fragments thereof.
16. The method of claim 14, wherein the soluble polypeptide has the amino
acid sequence set forth in SEQ ID NO: 34.
17. The method of claim 15, wherein the soluble polypeptide has the ammo
acid sequence set forth in SEQ ID NO:35.
18. The method of claim 9, wherein the EL- 17F inhibitory polynucleotide
comprises the nucleotide sequence set forth in, or a nucleotide sequence
complementary to the nucleotide sequence set forth in, SEQ ID NO:1 or a
fragment of SEQ ID NO: 1, or an RNA equivalent thereof, and wherein expression
of the inhibitory polynucleotide in a cell results in the decreased expression of
IL-17F.
19. The method of claim 9, wherein the IL-17R inhibitory polynucleotide
comprises the nucleotide sequence set forth in, or a nucleotide sequence
complementary to the nucleotide sequence set forth in, SEQ ID NO:5 or a
fragment of SEQ ID NO: 5, or an RNA equivalent thereof, and wherein expression
of the inhibitory polynucleotide in a cell results in the decreased expression of
IL-17R.

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20. The method of claim 9, wherein the EL- 17RC inhibitory polynucleotide
comprises a nucleotide sequence selected from the group consisting of the
nucleotide sequences set forth in, or a nucleotide sequence complementary to a
nucleotide sequence selected from the group consisting of the nucleotide sequences
set forth in, SEQ ID NO;7, SEQ ID NO:9, SEQ ID NO: 11, SEQ ID NO: 13, and
SEQ ID NO: 15 or a fragment of a nucleotide sequence selected from the group
consisting, of the nucleotide sequences set forth in SEQ ID NO:7, SEQ ID NO:9,
SEQ ID NO:11, SEQ ID NO:13, and SEQ ID NO:15, or an KNA equivalent
thereof, and wherein expression of the inhibitory polynucleotide in a cell results in
the decreased expression of IL-17RC.
21. The method of claim 8, wherein the disorder related to increased IL-17F
signaling is an inflammatory disorder.
22. The method of claim 21, wherein the inflammatory disorder is selected
from the group consisting of an autoimmune disease, a respiratory disease, and an
inflammatory bowel disease.
23. The method of claim 22, wherein the inflammatory disorder is an
autoimmune disease, and the autoimmune disease is selected from the group
consisting of arthritis, psoriasis, systemic lupus erythematosus, and multiple
sclerosis.
24. The method of claim 23, wherein the autoimmune disease is rheumatoid
arthritis.
25. The method of claim 22, wherein the inflammatory disorder is a respiratory .
disease, and the respiratory disease is cystic fibrosis.
26. The method of claim 22, wherein the inflammatory disorder is an
inflammatory bowel disease.

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27. The method of claim 8, further comprising administering to the subject a
therapeutically effective amount of at least one additional therapeutic agent.
28. The method of claim 27, wherein the at least one.additional therapeutic
agent is selected from the group consisting of cytokine inhibitors, growth factor
inhibitors, inununosuppressants, anti-infianiinatory agents, metabolic inhibitors,
enzyme inhibitors, cytotoxic agents, and cytostatic agents.
29. The method of claim 27, wherein the at least one additional therapeutic
agent is selected from the group consisting of TNF antagonists, anti-TNF agents,
IL-12 antagonists, IL-15 antagonists, IL-17 antagonists, IL-18 antagonists, IL-22
antagonists, T cell-depleting agents, B cell-depleting agents, cyclosporin, FK-506,
CCI-779, etanercept, infliximab, rituximab, adalimumab, prednisolone,
azathioprine, gold, sulphasalazine, chloroquine, hydroxychloroquine, minocycline,
anakinra, abatacept, methotrexate, lefiunomide, rapamycin, rapamycin analogs,
Cox-2 inhibitors, cPLA2 inhibitors, NSAIDs, p38 inhibitors, antagonists of B7.I,
B7.2, ICOSL, ICOS and/or CD28, and agonists of CTLA4.
30. A method of inhibiting the ability of NF-KB to activate NF-icB-responsive
promoters in a cell population or a subject, comprising administering an IL-17F
signaling antagonist to the cell population or the. subject.
31. The method of claim 3 0, wherein the IL-17F signaling antagonist is
selected from the group consisting of IL-17F inhibitory polynucleotides, IL-17R
inhibitory polynucleotides, IL-17RC inhibitory polynucleotides, soluble
polypeptides comprising IL-17R or IL-17F binding fragments thereof, soluble
polypeptides comprising IL-17RC or EL-17F binding fragments thereof, inhibitory
anti-IL-17F antibodies, inhibitory anti-IL-17R antibodies, inhibitory IL-17RC
antibodies, and antagonistic small molecules.
32. A method for inhibiting an IL-17F bioactivity in a cell population or a
subject, the method comprising administering an EL-17F signaling antagonist to the
cell population or the subject.

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33. The method of claim 32, wherein the IL-17F signaling antagonist is
selected from the group consisting of EL-17F inhibitory polytrucleotides, IL-17R
inhibitory polynucleo tides, IL-17RC inhibitory polynucleotides, soluble
polypeptides comprising IL-17R or IL-17F binding fragments thereof, soluble
polypeptides comprising IL-17RC or IL-17F binding fragments thereof, inhibitory
anti-IL-17F antibodies, inhibitory anti-IL-17R antibodies, inhibitory IL-17RC
antibodies, and antagonistic small molecules.
34. The method of claim 32, wherein the IL-17F bioactivity is selected from
the group consisting of neutrophil differentiation, neutropbil recraitment and
cytokine induction.
35. A pharmaceutical composition comprising an IL-17F signaling antagonist
and a pharmaceutically acceptable carrier.
36. The pharmaceutical composition of claim 35, wherein the IL-17F signaling
antagonist is selected from the group consisting of IL-17F inhibitory
polynucleotides, EL-17R inhibitory polynucleotides, IL-17RC inhibitory
polynucleotides, soluble polypeptides comprising IL-17R or IL-17F binding
fragments thereof, soluble polypeptides comprising IL-17RC or IL-17F binding
fragments thereof, inhibitory anti-IL-17F antibodies, inhibitory anti-IL-17R
antibodies, inhibitory IL-17RC antibodies, and antagonistic small molecules.
37. A vaccine adjuvant comprising an IL-17F signaling antagonist and an
antigen selected from the group consisting of an autoantigen, an allergen, an
alloantigen, and fragments thereof.
38. The vaccine adjuvant of claim 37, wherein the IL-17F signaling antagonist
is selected from fee group consisting of IL-17F inhibitory polynucleotides, IL-17R
inhibitory polynucleotides, IL-17RC inhibitory polynucleotides, soluble
polypeptides comprising IL-17R or IL-17F binding fragments thereof, soluble
polypeptides comprising TL-17RC or IL-17F binding fragments thereof, inhibitory

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anti-IL-17F antibodies, inhibitory anti-IL-17R antibodies, inhibitory IL-17RC
antibodies, and antagonistic small molecules.
39. An isolated antibody capable of specifically binding to the arnino acid
sequence set forth in SEQ ID NO:6.
40. An isolated antibody capable of specifically binding to an arnino acid
sequence selected from the group consisting of the arnino acid sequences set forth
in SEQ ID NO:7, SEQ ID NO:9, SEQ ID NO:11, SEQ ID NO:13, and SEQ ID
NO:15.
41. The antibody of claim 39, wherein the antibody antagonizes IL-17F
signaling.
42. The antibody of claim 40, wherein the antibody antagonizes IL-17F
signaling.
43. An isolated antibody capable of specifically binding to IL-17F protein.
44. The antibody of claim 43, wherein the IL-17F protein is derived from a
human or a primate.
45. The antibody of claim 43, wherein the IL-17F protein is multimeric.
46. The antibody of claim 45, wherein the IL-17F protein is IL-17F homodimer
or an JL-17F heterodimer.
47. The antibody of claim 46, wherein the IL-17F protein is a heterodimer, and
wherein the IL-17F heterodimer is IL-17A/IL-17F.
48. The antibody of claim 43, wherein the antibody inhibits IL-17F bioactivity.

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49. The method as in any one of claims 1-3 and 8, wherein IL-17F signaling is
mediated by IL-17F homodimer, an IL-17F heterodimer, or both IL-17F
homodimer and an IL-17F heterodimer.
50. The method of claim 49, wherein IL-17F signaling is mediated at least in
part by an IL-17F heterodimer, and wherein the IL-17F heterodimer is
IL-17A/IL-17F.
51. The method of claim 32, wherein the IL-17F bioactivity is mediated by
IL-17F homodimer, an IL-17F heterodimer, or both IL-17F homodimer and an IL-
17F leterodimer.
52. The method of claim 51, wherein the IL-17F bioactivity is mediated at least
in part by an IL-17F heterodimer, and wherein the IL-17F heterodimer is
IL-17A/IL-17F.
53. The pharmaceutical composition of claim 35, wherein the IL-17F signaling
antagonist antagonizes IL-17F homodimer, an IL-17F heterodimer, or both IL-17F
homodimer and an IL-17F heterodimer.
54. The vaccine adjuvant of claim 37, wherein the IL-17F signaling antagonist
antagonizes IL-17F homodimer, an IL-17F heterodimer, or both IL-17F
homodimer and an IL-17F heterodimer.
55. A method of inhibiting at least one activity associated with IL-21 signaling
comprising antagonizing IL-17F signaling.
56. A method of inhibiting at least one activity associated with IL-23 signaling
comprising antagonizing IL-17F signaling.
57. The method of claim 55, wherein IL-17F signaling is mediated by IL-17F
homodimer, an IL-17F heterodimer, or both IL-17F homodimer and an IL-17F
heterodimer.

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58. The method of claim 57, wherein IL-l7F signaling is mediated at least in
part by an IL-17F heterodimer, and wherein the IL-17F heterodimer is
IL-17A/IL-17F.
59. A method of purifying natural IL-17A protein comprising:
a) activating T cells in media; and
b) immunoprecipitating IL-17 A protein from the media.
60. A method of purifying natural IL-17F protein comprising:
a) activating T cells in media; and
b) immunoprecipitating IL-17F protein from the media.

61. The method of claim 59, wherein the IL-17A protein is IL-17A homodimer,
an IL-17 A heterodimer, or both IL-17A homodimer and an IL-17A heterodimer.
62. The method of claim 60, wherein the IL-17F protein is IL-17F homodimer,
anIL-17F heterodimer, or both IL-17F homodimer and anTL-17F heterodimer.
63. The method of claim 61, wherein the IL-17A protein is a heterodimer, and
wherein the IL-17A heterodimer is IL-17A/IL-17F.
64. The method of claim 62, wherein the IL-17F protein is a heterodimer, and
wherein the IL-17F heterodimer is IL-17A/IL-17F.
65. The method as in either claim 59 or 60, wherein the media comprises
IL-21.
66. An isolated IL-17F protein, wherein the IL-17F protein is IL-17F
homodimer or an IL-17F heterodimer.
67. The IL-17F protein of claim 66, wherein the IL-17F protein is isolated from
a natural source.

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68. The IL-17F protein of claim 67, wherein the natural source is at least one T
cell.
69. An isolated IL-17A protein, wherein the IL-17A protein is IL-17A
homodimer or an IL-17A heterodimer.
70. The IL-17A protein of claim 69, wherein the IL-17A protein is isolated
from a natural source.
71. The IL-17A protein of claim 70, wherein the natural source is at least one T
cell.
72. A method of inhibiting at least one activity associated with IL-17A
signaling, comprising administering an IL-17F antagonist.
73. A method of isolating IL-17A/IL-17F heterodimers substantially free from
IL-17Ahomodimers and IL-17Fhomodimers, comprising:
a) expressing an IL-17A fusion protein and an IL-17F fusion protein in
host cells cultured in media, wherein the IL-17A fusion protein
comprises an IL-17A protein or fragment thereof fused to a first affinity
tag, and wherein the IL-17F fusion protein comprises an IL-17F protein
or fragment thereof fused to a second affinity tag;
b) allowing the host cells to secrete the IL-17A fusion protein and IL-17F
fusion protein into the media;
c) placing the media over a first affinity column under nonreducing
conditions such that the IL-17A fusion protein binds to the first affinity
column;
d) eluting the bound protein from the first affinity column under
nonreducing conditions;
e) placing the eluent obtained from step d) over a second affinity column
under nonreducing conditions such that the IL-17F fusion protein binds
to the second affinity column; and

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f) eluting the bound protein from Hie second affinity column under
nonreducing conditions,
wherein the eluent obtained from step f) contains both IL-17A frxsion protein and
IL-17F fusion protein in the form of IL-17A/IL-17F heterodimers.
74. A method of isolating IL-17A/IL.-17F heterodimers substantially free from
IL-17A homodimers and IL-17F homodimers, comprising:
a) expressing an IL-17A fusion protein and an IL-17F fusion protein in
host cells cultured in media, wherein the 1L-17F fusion protein
comprises an IL-17F protein or fragment thereof fused to a first affinity
tag, and wherein the IL-17A fusion protein comprises an IL-17A
protein or fragment thereof fused to a second affinity tag;
b) allowing the host cells to secrete the IL-17A fusion protein and IL-17F
fusion protein into the media;
c) placing the media over a first affinity column under nonreducing
conditions such that the IL-17F fusion protein binds to the first affinity
column;
d) eluting the bound protein from the first affinity column under
nonreducing conditions;
e) placing the eluent obtained from step d) over a second affinity column
under nonreducing conditions such that the IL-17A fusion protein binds
to the second affinity column; and
f) eluting the bound protein from the second affinity column under
nonreducing conditions,
wherein the eluent obtained from step f) contains both IL-17A fusion protein and
IL-17F fusion protein in the form of IL-17A/IL-17F heterodimers.
75. An IL-17A/IL-17F heterodimer isolated according to the method as in
either claim 73 or 74.

The present invention provides isolated and purified polynucleotides and polypeptides related to the IL-17F signaling pathway. The invention also provides antibodies to IL-17F homodimers and IL-17A/IL-17F heterodimers, and methods of
isolating and purifying members of the IL-17 family, including IL-17A/IL-17F heterodimers, from a natural source. The present
invention also is directed to novel methods for diagnosing, prognosing, monitoring the progress of, and treating and/or preventing
disorders related to IL-17F signaling, i.e.,IL-17F-associated disorders, including, but not limited to, inflammatory disorders, such as
autoimmune diseases (e.g., arthritis (including rheumatoid arthritis), psoriasis, systemic lupus erythematosus, and multiple sclerosis),
respiratory diseases (e.g., COPD, cystic fibrosis, asthma, allergy), transplant rejection (including solid organ transplant rejection),
and inflammatory bowel diseases or disorders (IBDs, e.g., ulcerative colitis, Crohn's disease). The present invention is further directed to novel therapeutics and therapeutic targets, and to methods of screening and assessing test compounds for the intervention
(treatment) and prevention of disorders related to IL-17F signaling.