Anti-CD3 antibodies, anti-CD123 antibodies and bispecific antibodies specifically binding to CD3 and/or CD123

The present invention concerns antibody-like binding protein specifically binding to CD3 and binding specifically to at least one further antigen, for example CD123. The invention further concerns anti-CD3 antibodies and anti-CD123 antibodies. The present invention also concerns antibody-like binding protein specifically binding to CD123 and binding specifically to at least one further antigen. The invention also relates to pharmaceutical compositions comprising the antibody-like binding protein, anti-CD3 antibodies or anti-CD123 antibodies of the invention, and their use to treat cancer. The invention further relates to isolated nucleic acids, vectors and host cells comprising a sequence encoding said antibody-like binding protein, anti-CD3 or anti-CD123 antibody and the use of said anti-CD123 antibody as a diagnostic tool.

The first generation of bispecific antibodies was developed over 20 years ago.

Since then a number of clinical studies have tested bispecific antibodies engineered to target cancer cell surface antigens. This group of anti-cancer fusion proteins contains two or more functional domains that localize immunological effector cells in the proximity of targeted cancer cells to achieve anti-cancer activity.

As bispecific antibody technology developed, a different group of fusion proteins named bispecific T-cell engagers (BiTE) were generated by connecting two antibody single chain variable regions (scFv) only (no Fc amino acid segments were included) with a flexible linker, one scFv binds targeted cells and the other binds CD3 on T cell surface. One BiTE, blinatumomab, with CD19xCD3 bi-specific binding activities showed promising results in Phase II clinical trials for patients with minimal residual disease in B-lineage acute lymphoblastic.

CD123 (the interleukin-3 receptor alpha chain IL-3Ra) is a tumor antigen over-expressed in a variety of hematological neoplasms. The majority of AML blasts express surface CD123 and this expression does not vary by subtype of AML. Higher expression of CD123 on AML at diagnosis has been reported to be associated with poorer prognosis. It has been reported that CD123 is expressed on leukemic stem cells (LSCs). There is growing evidence to suggest that AML arises from these leukemic stem cells

(LSCs) which have been shown to be quiescent and relatively resistant to DNA damaging chemotherapy.

The increased expression of CD123 on LSCs compared with hematopoietic stem cells (HSCs) presents thus an opportunity for therapeutic targeting of AML-LSCs.

The monoclonal antibody (MAb) 7G3, raised against CD123, has previously been shown to inhibit IL-3 mediated proliferation and activation of both leukemic cell lines and primary cells (US Patent No. 6,177,078). However, it has remained unclear whether targeting CD123 can functionally impair AML-LSCs.

The use of CD123xCD3 antibody-like binding protein leads to tumor cell killing, as herein shown by the inventors.

The idea of producing a bispecific antibody-like binding protein with CD123xCD3 bi-specific binding activities has already been proposed and described in the international patent application WO2013/173820.

Furthermore, a CD123 x CD3 Dual Affinity Re-Targeting (DART) Bi-Specific Antibody Based Molecule from MacroGenics entered phase I clinical trials in 2014.

However, as shown by the inventors, the CD123xCD3 Dual Affinity Re-Targeting (DART) Bi-Specific Antibody Based Molecule from MacroGenics, for example, has an activation of 82% of CD4+ expressing T-cells and 83% of CD8+ expressing T-cells in the absence of target cells. The inappropriate activation of T-cells may lead to severe side effects, such as the cytokine release syndrome. The cytokine release syndrome refers to the release of cytokines by the activated T cells producing a type of systemic inflammatory response similar to that found in severe infections and characterized by hypotension, pyrexia and rigors. Deaths due to cytokine release syndrome have been reported for example for OKT3.

Therefore, in spite of these advancements in bispecific antibody technology, there remains a need for additional cancer therapeutics, particularly those that efficiently target and kill cancer cells, either directly or indirectly.

The inventors have succeeded in generating, screening and selecting specific rat anti-CD3 antibodies displaying high affinity for both human and Macaca fascicularis CD3 protein.

The inventors developed antibody-like binding proteins having biological and immunological specificity to the antigen CD3 and at least one further target antigen. In one example, to demonstrate the use of these anti-CD3 antibodies in the generation of bispecific antibody-like binding proteins the inventors generated anti-CD3/anti-CD123 antibody-like binding proteins and demonstrated the therapeutic use thereof. Those bispecific anti-CD3/anti-CD123 antibody-like binding proteins have a low T-cell activation, as it has been observed for the anti-CD3 antibody alone. However, once the CD 123 expressing target cells, such as THP-1 cells, are present the bispecific anti-CD3/anti-CD123 antibody-like binding protein shows a high activation of T-cells. Accordingly, the anti-CD3 antibody of the invention defined above is particularly useful for the preparation of antibody-like binding proteins of the invention.

Definitions

Throughout the instant application, the term "and/or" is a grammatical conjunction that is to be interpreted as encompassing that one or more of the cases it connects may occur. For example, the wording "such native sequence proteins can be prepared using standard recombinant and/or synthetic methods" indicates that native sequence proteins can be prepared using standard recombinant and synthetic methods or native sequence proteins can be prepared using standard recombinant methods or native sequence proteins can be prepared using synthetic methods.

Furthermore, throughout the instant application, the term "comprising" is to be interpreted as encompassing all specifically mentioned features as well optional, additional, unspecified ones. As used herein, the use of the term "comprising" also discloses the embodiment wherein no features other than the specifically mentioned features are present (i.e. "consisting of"). Furthermore the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The term "gene" means a DNA sequence that codes for, or corresponds to, a particular sequence of amino acids which comprises all or part of one or more proteins or enzymes, and may or may not include regulatory DNA sequences, such as promoter sequences, which determine for example the conditions under which the gene is expressed. Some genes, which are not structural genes, may be transcribed from DNA to RNA, but are not translated into an amino acid sequence. Other genes may function as regulators of structural genes or as regulators of DNA transcription. In particular, the term gene may be intended for the genomic sequence encoding a protein, i.e. a sequence comprising regulator, promoter, intron and exon sequences.

A sequence "at least 85% identical to a reference sequence" is a sequence having, on its entire length, 85%, or more, in particular 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with the entire length of the reference sequence.

In the context of the present application, the "percentage of identity" is calculated using a global pairwise alignment (i.e. the two sequences are compared over their entire length). Methods for comparing the identity of two or more sequences are well known in the art. The « needle » program, which uses the Needleman-Wunsch global alignment algorithm (Needleman and Wunsch, 1970 J. Mol. Biol. 48:443-453) to find the optimum alignment (including gaps) of two sequences when considering their entire length, may for example be used. The needle program is for example available on the ebi.ac.uk World Wide Web site. The percentage of identity between two polypeptides, in accordance with the invention, is calculated using the EMBOSS: needle (global) program with a "Gap Open" parameter equal to 10.0, a "Gap Extend" parameter equal to 0.5, and a Blosum62 matrix.

Proteins consisting of an amino acid sequence "at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical" to a reference sequence may comprise mutations such as deletions, insertions and/or substitutions compared to the reference sequence. In case of substitutions, the protein consisting of an amino acid sequence at least 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% identical to a reference sequence may correspond to a homologous sequence derived from another species than the reference sequence.

"Amino acid substitutions" may be conservative or non-conservative. Preferably, substitutions are conservative substitutions, in which one amino acid is substituted for another amino acid with similar structural and/or chemical properties. The substitution preferably corresponds to a conservative substitution as indicated in the table below.

Conservative substitutions Type of Amino Acid

Ala, Val, Leu, lie, Met, Pro, Phe,

Amino acids with aliphatic hydrophobic side chains Trp

Ser, Tyr, Asn, Gin, Cys Amino acids with uncharged but polar side chains

Asp, Glu Amino acids with acidic side chains

Lys, Arg, His Amino acids with basic side chains

Gly Neutral side chain

An "antibody" also called "immunoglobulin" may be a natural or conventional antibody in which two heavy chains are linked to each other by disulfide bonds and each heavy chain is linked to a light chain by a disulfide bond. There are two types of light chain, lambda (I) and kappa (k). There are five main heavy chain classes (or isotypes) which determine the functional activity of an antibody molecule: IgM, IgD, IgG, IgA and IgE. Each chain contains distinct sequence domains. The light chain includes two domains or regions, a variable domain (VL) and a constant domain (CL). The heavy chain includes four domains, a variable domain (VH) and three constant domains (CH1 , CH2 and CH3, collectively referred to as CH). The variable regions of both light (VL) and heavy (VH) chains determine binding recognition and specificity to the antigen. The constant region domains of the light (CL) and heavy (CH) chains confer important biological properties such as antibody chain association, secretion, trans-placental mobility, complement binding, and binding to Fc receptors (FcR). The Fv fragment is the N-terminal part of the Fab fragment of an immunoglobulin and consists of the variable portions of one light chain and one heavy chain. The specificity of the antibody resides in the structural complementarity between the antibody combining site and the antigenic determinant. Antibody combining sites are made up of residues that are primarily from the hypervariable or complementarity determining regions (CDRs). Occasionally, residues from nonhypervariable or framework regions (FR) influence the overall domain structure and hence the combining site. Complementarity Determining Regions or CDRs refer to amino acid sequences that together define the binding affinity and specificity of the natural Fv region of a native immunoglobulin binding site. The light and heavy chains of an immunoglobulin each have three CDRs, designated CDR1 -L, CDR2-L, CDR3-L and CDR1-H, CDR2-H, CDR3-H, respectively. A conventional antibody antigen-binding site, therefore, includes six CDRs, comprising the CDR set from each of a heavy and a light chain V region.

In context of the invention, the antibody or immunoglobulin is an IgM, IgD, IgG, IgA and IgE.

"Framework Regions" (FRs) refer to amino acid sequences interposed between CDRs, i.e. to those portions of immunoglobulin light and heavy chain variable regions that are relatively conserved among different immunoglobulins in a single species. The light and heavy chains of an immunoglobulin each have four FRs, designated FR1-L, FR2-L, FR3-L, FR4-L, and FR1 -H, FR2-H, FR3-H, FR4-H, respectively. Accordingly, the light chain variable domain may thus be designated as (FR1-L)-(CDR1 -L)-(FR2-L)-(CDR2-L)-(FR3-L)-(CDR3-L)-(FR4-L) and the heavy chain variable domain may thus be designated as (FR1-H)-(CDR1-H)-(FR2-H)-(CDR2-H)-(FR3-H)-(CDR3-H)-(FR4-H).

Knowing the amino acid sequence of the CDRs one skilled in the art can easily determine the framework regions FR1 -L, FR2-L, FR3-L, FR4-L and/or FR1-H, FR2-H, FR3-H, FR4-H.

As used herein, a "human framework region" is a framework region that is substantially identical (about 85%, or more, in particular 90%, 95%, 97%, 99% or 100%) to the framework region of a naturally occurring human antibody.

In the context of the invention, CDR/FR definition in an immunoglobulin light or heavy chain is to be determined based on IMGT definition (Lefranc et al. Dev. Comp. Immunol., 2003, 27(1 ):55-77; www.imgt.org).

As used herein, the term "antibody" denotes conventional antibodies and fragments thereof, as well as single domain antibodies and fragments thereof, in particular variable heavy chain of single domain antibodies, and chimeric, humanized, bispecific or multispecific antibodies.

As used herein, antibody or immunoglobulin also includes "single domain antibodies" which have been more recently described and which are antibodies whose complementary determining regions are part of a single domain polypeptide. Examples of single domain antibodies include heavy chain antibodies, antibodies naturally devoid of light chains, single domain antibodies derived from conventional four-chain antibodies, engineered single domain antibodies. Single domain antibodies may be derived from any species including, but not limited to mouse, human, camel, llama, goat, rabbit, bovine. Single domain antibodies may be naturally occurring single domain antibodies known as heavy chain antibody devoid of light chains. In particular, Camelidae species, for example camel, dromedary, llama, alpaca and guanaco,

produce heavy chain antibodies naturally devoid of light chain. Camelid heavy chain antibodies also lack the CH1 domain.

The variable heavy chain of these single domain antibodies devoid of light chains are known in the art as "VHH" or "nanobody". Similar to conventional VH domains, VHHs contain four FRs and three CDRs. Nanobodies have advantages over conventional antibodies: they are about ten times smaller than IgG molecules, and as a consequence properly folded functional nanobodies can be produced by in vitro expression while achieving high yield. Furthermore, nanobodies are very stable, and resistant to the action of proteases. The properties and production of nanobodies have been reviewed by Harmsen and De Haard HJ (Appl. Microbiol. Biotechnol. 2007 Nov;77(1 ):13-22).

The term "monoclonal antibody" or "mAb" as used herein refers to an antibody molecule of a single amino acid composition that is directed against a specific antigen, and is not to be construed as requiring production of the antibody by any particular method. A monoclonal antibody may be produced by a single clone of B cells or hybridoma, but may also be recombinant, i.e. produced by protein engineering.

The term "chimeric antibody" refers to an engineered antibody which in its broadest sense contains one or more regions from one antibody and one or more regions from on or more other antibody(ies). In particular a chimeric antibody comprises a VH domain and a VL domain of an antibody derived from a non-human animal, in association with a CH domain and a CL domain of another antibody, in particular a human antibody. As the non-human animal, any animal such as mouse, rat, hamster, rabbit or the like can be used. A chimeric antibody may also denote a multispecific antibody having specificity for at least two different antigens.

The term "humanized antibody" refers to an antibody which is wholly or partially of non-human origin and which has been modified to replace certain amino acids, in particular in the framework regions of the heavy and light chains, in order to avoid or minimize an immune response in humans. The constant domains of a humanized antibody are most of the time human CH and CL domains.

Numerous methods for humanization of an antibody sequence are known in the art; see e.g. the review by Almagro & Fransson (2008) Front Biosci. 13: 1619-1633. One commonly used method is CDR grafting, or antibody reshaping, which involves grafting of the CDR sequences of a donor antibody, generally a mouse antibody, into the framework scaffold of a human antibody of different specificity. Since CDR grafting may reduce the binding specificity and affinity, and thus the biological activity, of a CDR grafted non-human antibody, back mutations may be introduced at selected positions of the CDR grafted antibody in order to retain the binding specificity and affinity of the parent antibody. Identification of positions for possible back mutations can be performed using information available in the literature and in antibody databases. Amino acid residues that are candidates for back mutations are typically those that are located at the surface of an antibody molecule, while residues that are buried or that have a low degree of surface exposure will not normally be altered. An alternative humanization technique to CDR grafting and back mutation is resurfacing, in which non-surface exposed residues of non-human origin are retained, while surface residues are altered to human residues. Another alternative technique is known as "guided selection" (Jespers et al. (1994) Biotechnology 12, 899) and can be used to derive from for example a murine or rat antibody a fully human antibody conserving the epitope and binding characteristics of the parental antibody. A further method of humanization is the so-called 4D humanization. The 4D humanization protocol is described in the patent application US201 10027266 A1 (WO2009032661A1 ) and is exemplified in the following applying the 4D humanization to humanize the rat antibody variable light (VL) and heavy (VH) domains. In one example, a rat antibody homology model was done with typically MOE software (v. 201 1.10- Chemical Computing Group, Quebec, Canada) using PDB structures (Berman et al., Nucleic Acids Research, 2000, 28:235-242) as templates and was subsequently energy minimized using the standard procedures implemented in MOE. A molecular dynamics (MD) simulation was then performed on the minimized 3D homology model (done with MOE software) of rat antibody and compared to the, for example, 49 human models derived from the seven representative light chains (vk1 , vk2, vk3, vk4, vlambdal , vlambda2, vlambda3) and the seven representative heavy chains (vhl a, vhl b, vh2, vh3, vh4, vh5, vh6) designed by LGCR/SDI and available within MOE. For instance, one model of chains couple (Vkx-Vhx) with the best both hydrophobic, electrostatic components and sequence identity outside CDR has been selected for the "4D humanization". For the pairwise association between the rat antibody variable domain and the selected model, the sequences were aligned based typically on the optimal 3D superposition of the alpha carbons of the corresponding homology models. The unwanted motifs were then considered and mutated. Finally, the resulting humanized sequences were blasted for sequence similarity against, for instance, the IEDB database (http://www.immuneepitope.org; version 2012/01/30

accessible locally) to ensure that none of the sequences contain any known B- or T-cell epitope listed in.

For chimeric antibodies, humanization typically involves modification of the framework regions of the variable region sequences.

Amino acid residues that are part of a CDR will typically not be altered in connection with humanization, although in certain cases it may be desirable to alter individual CDR amino acid residues, for example to remove a glycosylation site, a deamidation site or an undesired cysteine residue. N-linked glycosylation occurs by attachment of an oligosaccharide chain to an asparagine residue in the tripeptide sequence Asn-X-Ser or Asn-X-Thr, where X may be any amino acid except Pro. Removal of an N-glycosylation site may be achieved by mutating either the Asn or the Ser/Thr residue to a different residue, in particular by way of conservative substitution. Deamidation of asparagine and glutamine residues can occur depending on factors such as pH and surface exposure. Asparagine residues are particularly susceptible to deamidation, primarily when present in the sequence Asn-Gly, and to a lesser extent in other dipeptide sequences such as Asn-Ala. When such a deamidation site, in particular Asn-Gly, is present in a CDR sequence, it may therefore be desirable to remove the site, typically by conservative substitution to remove one of the implicated residues. Substitution in a CDR sequence to remove one of the implicated residues is also intended to be encompassed by the present invention.

"Fragments" of (conventional) antibodies comprise a portion of an intact antibody, in particular the antigen binding region or variable region of the intact antibody. Examples of antibody fragments include Fv, Fab, F(ab')2, Fab', dsFv, (dsFv)2, scFv, sc(Fv)2, diabodies, bispecific and multispecific antibodies formed from antibody fragments. A fragment of a conventional antibody may also be a single domain antibody, such as a heavy chain antibody or VHH.

The term "Fab" denotes an antibody fragment having a molecular weight of about 50,000 and antigen binding activity, in which about a half of the N-terminal side of H chain and the entire L chain, among fragments obtained by treating IgG with a protease, papaine, are bound together through a disulfide bond.

The term "F(ab')2" refers to an antibody fragment having a molecular weight of about 100,000 and antigen binding activity, which is slightly larger than the Fab bound via a disulfide bond of the hinge region, among fragments obtained by treating IgG with a protease, pepsin.

The term Tab' " refers to an antibody fragment having a molecular weight of about 50,000 and antigen binding activity, which is obtained by cutting a disulfide bond of the hinge region of the F(ab')2.

A single chain Fv ("scF ") polypeptide is a covalently linked VH::VL heterodimer which is usually expressed from a gene fusion including VH and VL encoding genes linked by a peptide-encoding linker. The human scFv fragment of the invention includes CDRs that are held in appropriate conformation, in particular by using gene recombination techniques. Divalent and multivalent antibody fragments can form either spontaneously by association of monovalent scFvs, or can be generated by coupling monovalent scFvs by a peptide linker, such as divalent sc(Fv)2. "dsFv" is a VH::VL heterodimer stabilised by a disulphide bond. "(dsFv)2" denotes two dsFv coupled by a peptide linker.

The term "bispecific antibody" or "BsAb" typically denotes an antibody, which combines the antigen-binding sites of two antibodies within a single molecule. Thus, BsAbs are able to bind two different antigens simultaneously. Genetic engineering has been used with increasing frequency to design, modify, and produce antibodies or antibody derivatives with a desired set of binding properties and effector functions as described for instance in EP 2 050 764 A1.

The term "multispecific antibody" denotes an antibody that combines the antigen-binding sites of two or more antibodies within a single molecule.

The term "diabodies" refers to small antibody fragments with two antigen-binding sites, which fragments comprise a heavy-chain variable domain (VH) connected to a light-chain variable domain (VL) in the same polypeptide chain (VH-VL). By using a linker that is too short to allow pairing between the two domains on the same chain, the domains are forced to pair with the complementary domains of another chain and create two antigen-binding sites.

The term "hybridoma" denotes a cell, which is obtained by subjecting a B cell prepared by immunizing a non-human mammal with an antigen to cell fusion with a myeloma cell derived from a mouse or the like which produces a desired monoclonal antibody having an antigen specificity.

By "purified" and "isolated" it is meant, when referring to a polypeptide (i.e. the antibody of the invention) or a nucleotide sequence, that the indicated molecule is present in the substantial absence of other biological macromolecules of the same type. The term "purified" as used herein in particular means at least 75%, 85%, 95%, or 98% by weight, of biological macromolecules of the same type are present. An "isolated" nucleic acid molecule that encodes a particular polypeptide refers to a nucleic acid molecule that is substantially free of other nucleic acid molecules that do not encode the subject polypeptide; however, the molecule may include some additional bases or moieties, which do not deleteriously affect the basic characteristics of the composition.

The term "antigen" or "target antigen" as used herein refers to a molecule or a portion of a molecule that is capable of being bound by an antibody or an antibody-like binding protein. The term further refers to a molecule or a portion of a molecule that is capable of being used in an animal to produce antibodies that are capable of binding to an epitope of that antigen. A target antigen may have one or more epitopes. With respect to each target antigen recognized by an antibody or by an antibody-like binding protein, the antibody-like binding protein is capable of competing with an intact antibody that recognizes the target antigen.

"Affinity" is defined, in theory, by the equilibrium association between the whole antibody and the antigen. Affinity may be expressed for example in half-maximal effective concentration (EC50) or the equilibrium dissociation constant (KD).

"Half maximal effective concentration" also called "EC50" refers to the concentration of a drug, antibody or toxicant which induces a response halfway between the baseline and maximum after a specified exposure time. EC50 and affinity are inversely related, the lower the EC50 value the higher the affinity of the antibody.

"KD" is the equilibrium dissociation constant, a ratio of k0ff/k0n, between the antibody and its antigen. KD and affinity are inversely related. The KD value relates to the concentration of antibody and the lower the KD value and the higher the affinity of the antibody. Affinity can be experimentally assessed by a variety of known methods, such as measuring association and dissociation rates with surface Plasmon resonance or measuring the EC50 in an immunochemical assay (ELISA, FACS). Enzyme-linked immunosorbent assay (ELISA) is a biochemistry assay that uses a solid-phase enzyme immunoassay to detect the presence of a substance, usually an antigen, in a liquid sample or wet sample. Antigens from the sample are attached to a surface. Then, a further specific antibody is applied over the surface so it can bind to the antigen. This antibody is linked to an enzyme, and, in the final step, a substance containing the enzyme's substrate is added. The subsequent reaction produces a detectable signal, most commonly a color change in the substrate. Fluorescence-activated cell sorting (FACS) provides a method for sorting a heterogeneous mixture of biological cells into

two or more containers, one cell at a time, based upon the specific light scattering and fluorescent characteristics of each cell. In these assays, the EC5o is the concentration of the antibody which induces a response halfway between the baseline and maximum after some specified exposure time on a defined concentration of antigen by ELISA (enzyme-linked immuno-sorbent assay) or cell expressing the antigen by FACS (Fluorescence Activated Cell Sorting). Surface plasmon resonance is a label free method wherein the binding of a molecule in the soluble phase (the "analyte") is directly measured to a "ligand" molecule immobilized on a sensor surface. In the sensor device the binding of the ligand is monitored by an optical phenomenon termed surface plasmon. In particular, when the "analyte" molecule dissociates from the "ligand" molecule, a decrease in SPR signal (expressed in resonance units, RU) is observed. Association ('on rate', ka) and Dissociation rates ('off rate', kd) are obtained from the signal obtained during the association and dissociation and the equilibrium dissociation constant ('binding constant', KD) can be calculated therefrom. The signal given in resonance units (RU) depends on the size of the ligand present in the analyte, however in case the experimental conditions are the same, i.e. the ligand is the same molecule at the same condition the obtained RU can indicate affinity, wherein the higher the obtained signal in RU the higher the binding.

A monoclonal antibody binding to antigen 1 (Ag1 ) is "cross-reactive" to antigen 2 (Ag2) when the EC5oS are in a similar range for both antigens. In the present application, a monoclonal antibody binding to Ag1 is cross-reactive to Ag2 when the ratio of affinity of Ag2 to affinity of Ag1 is equal or less than 10 (in particular 5, 2, 1 or 0.5), affinities being measured with the same method for both antigens.

A monoclonal antibody binding to Ag1 is "not significantly cross-reactive" to Ag2 when the affinities are very different for the two antigens. Affinity for Ag2 may not be measurable if the binding response is too low. In the present application, a monoclonal antibody binding to Ag1 is not significantly cross-reactive to Ag2, when the binding response of the monoclonal antibody to Ag2 is less than 5% of the binding response of the same monoclonal antibody to Ag1 in the same experimental setting and at the same antibody concentration. In practice, the antibody concentration used can be the EC5o or the concentration required to reach the saturation plateau obtained with Ag1 .

As used herein "specificity" denotes the capacity of an antibody to discriminate the target peptide sequence to which its binds ("epitope") from closely related, highly homologous, peptide sequences.

A monoclonal antibody "binds specifically" to Ag1 when it is not significantly cross-reactive to Ag2.

A "domain" may be any region of a protein, generally defined on the basis of sequence homologies and often related to a specific structural or functional entity.

A "recombinant" molecule is one that has been prepared, expressed, created, or isolated by recombinant means.

As used herein, the term "subject" denotes a mammal, such as a rodent, a feline, a canine, and a primate. In particular, a subject according to the invention is a human.

Anti CD3 antibodies

"CD3" denotes an antigen that is expressed on T-cells as part of the multimolecular T-cell receptor complex and that consists of at least three different chains CD3£, CD35 and CD3y. CD35 and CD3y have a low sequence identity and/or similarity to human CD3£ (similarity and identity is less than 20%). CD3£ and CDR35 can form together a complex, herein called "CD3£/5-complex". CD3£ also forms a complex with CDR3y, the so-called "CD3£/Y-complex" Clustering of CD3 on T-cells, e.g., by immobilized anti-CD3-antibodies, leads to T-cell activation similar to the engagement of the T-cell receptor but independent from its clone typical specificity. "CD3E" comprises three domains, an intracellular domain, a transmembrane domain and an extracellular domain.

Most prior art anti-CD3-antibodies recognize the CD3£-chain. One of such prior art anti-CD3-antibodies is OKT3. Prior art has exemplified T cell activation events employing antibody molecules for example by employing the antibody molecule OKT3. The anti-CD3 antibody and variant thereof have been described in the prior art (US 4,361 ,549 ; US 4,361 ,549 ; US 5,885,573 ; US 5,929,212 ; and WO 98/52975 or US 5,955,358). OKT3 has been further used as potent immunosuppressive agent in clinical transplantation to treat allograft rejection (Thistlethwaite 1984, Transplantation 38, 695-701 ; Woodle 1991 , Transplantation 51 , 1207-1212; Choi 2001 , Eur. J. Immunol. 31 (1 ), 94-106).

Major drawbacks of this therapy are T cell activation manifested in cytokine release due to cross-linking between T cells and FcvR-bearing cells and the human anti-mouse antibody (HAMA) response. Several publications have described alterations such as humanization of OKT3 to reduce these side effects: US 5,929,212; US 5,885,573 and others. On the other hand, OKT3 or other anti-CD3-antibodies can be

used as immunopotentiating agents to stimulate T cell activation and proliferation (US 6,406,696 Bluestone; US 6,143,297 Bluestone; US 6,1 13,901 Bluestone; Yannelly 1990, J. Immunol. Meth. 1 , 91 -100). Anti-CD3-anti bodies have also been described as agents used in combination with anti-CD28-antibodies to induce T cell proliferation (US 6,352,694). OKT3 has further been used by itself or as a component of a bispecific antibody to target cytotoxic T cells to tumor cells or virus infected cells (Nitta 1990, Lancet 335, 368-376; Sanna 1995, Bio/Technology 13, 1221-1224; WO 99/54440).

Approaches up to now using antibodies as agents for recruiting T-cells have been hampered by several findings. First, natural or engineered antibodies having a high binding affinity to T-cells often do not activate the T-cells to which they are bound. Second, natural or engineered antibodies having a low binding affinity to T-cells are also often ineffective with respect to their ability to trigger T-cell mediated cell lysis.

A reference sequence of full-length human CD3£ protein, including the signal peptide, is available from the Uniprot database under accession number P07766 and herein enclosed under SEQ ID NO: 1 (as available on December 12, 2014).

A reference sequence of full-length Macaca fascicularis CD3£ protein, including the signal peptide, is available from the Uniprot database under accession number Q95LI5 and herein enclosed under SEQ ID NO: 2 (as available on December 12, 2014).

A sequence of mature human CD3£ His-tagged Fc-fusion proteins, cloned by the inventors from genomic DNA, is disclosed under SEQ ID NO: 3. Said mature human CD3£ His-tagged Fc-fusion protein comprises amino acids 23 to 126 of the full-length human CD3£ protein and thus comprises the extracellular domain of human CD3£.

A sequence of mature Macaca fascicularis CD3£ Fc-fusion protein, cloned by the inventors from genomic DNA, is disclosed under SEQ ID NO: 4. Said mature Macaca fascicularis CD3£ Fc-fusion protein comprises amino acids 23 to 1 17 of the full-length Macaca fascicularis CD3£ protein and thus comprises the extracellular domain of human or Macaca fascicularis CD3£, containing one Alanine to Valine exchange at the amino acid position 35 in comparison to amino acid position 57 of the wild-type sequence.

Domain organization of human and Macaca fascicularis CD3£ is as it follows (based on Uniprot P07766 sequence (human) and Uniprot Q95LI5 sequence (Macaca fascicularis)):

CD3£ domains Positions on SEQ ID NO A Positions on SEQ ID NO : 2

(human) (Macaca fascicularis)

Extracellular 23 - 126 22 - 1 17

Transmembrane domain 127 - 152 1 18 - 138

Cytoplasmic 153 - 207 139 - 198

Accordingly, the extracellular domain of human CD3£ consists of amino acids at positions 23 - 126 of SEQ ID NO: 1 and the extracellular domain of Macaca fascicularis CD3£ consists of amino acids at positions 22 - 1 17 of SEQ ID NO: 2.

The inventors have succeeded in generating, screening and selecting specific mouse and rat anti-CD3 antibodies. These anti-CD3 antibodies display high affinity for both human and Macaca fascicularis CD3 protein, and have however a low T-cell activation in the absence of target cells.

The inventors have determined the sequence of variable heavy and light chains of such monoclonal antibodies, the so-called anti-CD3 antibodies "20G6-F3", "4B4-D7", "4E7-C9", "18F5-H10", "12D2-E5", "1 1 D7-C3", Ί 1 Η3-Ε5", "13H2-C2", "13C1 -F6", "18H1 1 -F10", "1 E6-C9", "10F4-C10", "10E6-G6", "18G9-H1 1 ", "1 1 F3-B9", "12G3-E8", "5B1-G2", "16F8-A7", "1 1 F9-F8", "3G5-E10", "9D7-F3", "8C2-F7", "20E5-F10", "20B5-F10", "6C9-C9", "3E8-G1 ", "3H6-D2" and "8H2".

The so-called "20G6-F3" anti-CD3 antibody comprises:

a heavy chain variable domain of consisting of sequence

EVQLVETGGSLVQPGKSLKLTCATSGFTFTKAWMHVWRQSPEKQLEVWAQIKDKSNS YATYYAESVKGRFTISRDDSKSTIYLQMNSLKEEDTAIYYCRGVYYALSPFDYWGQGVM VTVSS (SEQ ID NO: 5, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 6, a CDR2-H of sequence SEQ ID NO: 7, and a CDR3-H of sequence SEQ ID NO: 8, and

- a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQSLIYKVSN RFSGFSDRFSGSGSGTDFTLKISRVDPDDLGVYYCGQGTQYPFTFGSGTKLEIK (SEQ

ID NO: 9, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "4B4-D7" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGRLVQPGRSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKARSNN YATYYAESVKGRFTISRDDSKSTIYLQMNSLKEEDTAIYYCRGTYYASKPFDYWGQGVM VTVSS (SEQ ID NO: 12, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 14, and a CDR3-H of sequence SEQ ID NO: 15, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHDNGNTYLSWSLQRPGQSPQVLIYKVSN RFSGTSDRFTGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGSGTKLEIK (SEQ ID NO: 16, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 17, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "4E7-C9" anti-CD3 antibody comprises:

- a heavy chain variable domain consisting of sequence EVQVVETGGSLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKDKSNN YATYYAESLKGRFTISRDDPKRSIYLQMNSLREEDTAIYYCRYVHYGIGYAMDAWGQGT SVTVSS (SEQ ID NO: 18, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 19, and a CDR3-H of sequence SEQ ID NO: 20, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLEHNNGNTYLSWYLQKPGQSPQPLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGPGTKLELK (SEQ ID NO: 21 , with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 22, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "18F5-H10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQVVETGGSLVQPGKSLKLTCATSGFTFTNAWMHWVRRSPEKQLEVWAQIKDKSNN YATYYAESVKGRFTISRDDSKSSIYLQMNSLKEEDTAIYYCRYVHYRFAYALDAWGRGT SVSVSS (SEQ ID NO: 23, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 24, a CDR2-H of sequence SEQ ID NO: 19, and a CDR3-H of sequence SEQ ID NO: 25, and

a light chain variable domain consisting of sequence DVLMTQTPVSLSVSLGGQVSISCRSSQSLVHTNGNTYLSWYLQKPGQSPQLLIYKVSNR LSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTHYPFTFGAGTKLELK (SEQ ID NO: 26, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 27, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO:28.

The so-called "12D2-E5" anti-CD3 antibody comprises:

- a heavy chain variable domain consisting of sequence EVKLVESGGGLVQPGRSLRLSCAASGFNFYAYWMGVWRQAPGKGLEWIGEIKKDGTTI NYTPSLKDRFTISRDNAQNTLYLQMTKLGSEDTALYYCAREERDGYFDYWGQGVMVTV SS (SEQ ID NO: 29, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 30, a CDR2-H of sequence SEQ ID NO: 31 , and a CDR3-H of sequence SEQ ID NO: 32, and

a light chain variable domain consisting of sequence QFVLTQPNSVSTNLGSTVKLSCKRSTGNIGSNYVNWYQQHEGRSPTTMIYRDDKRPDG VPDRFSGSIDRSSNSALLTINNVQTEDEADYFCQSYSSGIVFGGGTKLTVL (SEQ ID NO: 33, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 34, a CDR2-L consisting of sequence 'RDD', and a CDR3-L of sequence SEQ ID NO: 35.

The so-called "1 1 D7-C3" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQFVETGGSLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEWVAQIKAKSNN YATYYAESVKGRFTISRDDSKSSVYLQMNSLKEEDTATYYCRGLYYGLSPSDYWGQGV MVTVSS (SEQ ID NO: 36, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 38, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQLLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTHYPFTFGSGTKLEIK (SEQ ID NO: 39, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 28.

The so-called "1 1 H3-E5" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSKSSVYLQMNSLKEEDTAIYYCRGTYYAYKPFDYWGQGV MVTVSS (SEQ ID NO: 40, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 41 , and

- a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHDNGNTYLSWSLQKPGQSPQVLIYKVSN RFSGTSDRFTGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGSGTKLEIK (SEQ ID NO: 42, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 17, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "13H2-C2" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EEELVETGGSLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPDKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSKSSVYLQMNNLKEEDTAIYYCRYVHYGLAPMDAWGQGT SVTVSS (SEQ ID NO: 43, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 44, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKAGQSPQLLIYKVSN RFSGISDRFSGSGSGTDFILKISRVEPDDLGVFYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 45, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "13C1 -F6" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGTLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSKTSVYLQLNSLREEDTAIYYCRGTQYGYNPFDYWGQGV MVTVSS (SEQ ID NO: 46, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 47, and

a light chain variable domain consisting of sequence DVVMTQSPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQRSGQSPQLLIYKVSN RLSGISDRFSGSGSGTDFTLKISRIEPDDLGVYYCGQGTQYPFTFGSGTRLEIK (SEQ ID NO: 48, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "18H1 1-F10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVESGGGLVQPGRSLKLSCAASGFIFSDYYMAWVRQAPKKGLEVWATISISGSRTY YPDSVKGRFTVSRDNAKSSLYLQMNSLKSEDTATYYCATNNPGGWFVYWGQGTLVTV SS (SEQ ID NO: 49, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 50, a CDR2-H of sequence SEQ ID NO: 51 , and a CDR3-H of sequence SEQ ID NO: 52, and

a light chain variable domain consisting of sequence NIQMTQSPSLLSASVGDRVTLSCKAGQNINNDLAWYQQKLGEAPRLLIYNANSLQTGIPS RFSGSGSGADFTLTISSLQPEDVATYFCQQYSSGDTFGAGTKLELK (SEQ ID NO: 53, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 54, a CDR2-L consisting of sequence 'NAN', and a CDR3-L of sequence SEQ ID NO: 55.

The so-called "1 E6-C9" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLKLTCATSGFTFSYAWMHVWRQSPDKQLQVWAQIKAKSNN YATYYAESVEGRFTISRDDSKSSVYLQMNSLKEEDTAIYYCRGVYYGLLGLDAWGQGT SVTVSS (SEQ ID NO: 56, with CDRs shown in bold characters and underlined)

comprising CDR1-H of sequence SEQ ID NO: 57, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 58, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVRLGGQVSISCRSSQSLVHNNGNTYLSWFLQKPGQSPQLLIYKVSN RFSGISDRFSGSASGTDFTLKISRVEPDDLGVYYCGQGTHYPFTFGSGTKLEIK (SEQ ID NO: 59, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 28.

The so-called "10F4-C10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLKITCATSGFTFSNAWMHWVRQSPEKQLEVWAQIKAKSNNY ATYYAESVKGRFTISRDDSKSSIYLQMNSLKEEDTAIYYCRAVNYGNYPLDYWGQGVMV TVSS (SEQ ID NO: 60, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 61 , and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWCLQKPGQSPQLLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 62, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "10E6-G6" anti-CD3 antibody comprises:

- a heavy chain variable domain consisting of sequence EVQLVETGGGLVQSGKSLKLTCATSGFTVTNAWMHVWRQSPEKQLEVWAQIKAKSNN YETYYAESVKGRFTISRDDSKSSVYLQMNSLKEEDTAIYYCRGTQYGYNPFDYWGQGV MVTVSS (SEQ ID NO: 63, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 64, a CDR2-H of sequence SEQ ID NO: 65, and a CDR3-L of sequence SEQ ID NO: 47, and

a light chain variable domain consisting of sequence DVVMTQSPVSLSVSLGGQVSISCRSSQSLVHNNGYTYLSWYLQKPGQSPQVFIYKVSN RFSGISDRFSGSGSGTDFTLKISRIEPDDLGVYYCGQGTHYPFTFGSGTKLEIK (SEQ ID NO: 66, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 67, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 28.

The so-called "18G9-H1 1 " anti-CD3 antibody comprises:

- a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLKLTCATSGFTFSNAWIQVWRQSPEKQLEVWAQIKAKSNNY ATYYAESVKGRFTISRDDSKSSVYLQMNSLKEEDTALYYCTWRHYYSSHTMDAWGQG TLVTVSS (SEQ ID NO: 68, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 69, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQLLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVAPTDLGVYYCGQGSQYPFTFGAGTKLELK (SEQ ID NO: 70, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 71.

The so-called "1 1 F3-B9" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLTLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSKRSVYLQMNSLKEEDTAIYYCRYVNYGLAPMDVWGQGT SVTVSS (SEQ ID NO: 72, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 84, and

- a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHDNGNTYLSWYLQKPGQSPQLLIYKVSN RFSGFSDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 73, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 17, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "12G3-E8" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVRVVETGGSLVQPGKSLKLTCATSGFTFSLAWMHWVRQSPEKKLEVWAQIKDKANN

YATYYAESVKGRFTISRDDSKRSVYLQMNRLKEEDTAIYYCRGVYYGFSMTPFDYWGQ

GVMVTVSS (SEQ ID NO: 74, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 75, a CDR2-H of sequence SEQ ID NO: 76, and a CDR3-H of sequence SEQ ID NO: 77, and

- a light chain variable domain consisting of sequence DVAMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQVLIYKVSN RFSGISDRFSGSGSGADFTLKISRVEPDDLGVYYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 78, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "5B1-G2" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQVVETGGSLVQPGKSLKLTCATSGFSFSNAWMHVWRQSPEKQLEVWAQIKDKANN YATYYAESVKGRFTISRDDSKGSIYLQMNSLKEEDTAVYYCRGLYYGLFPSDYWGQGV MVTVSS (SEQ ID NO: 79, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 80, a CDR2-H of sequence SEQ ID NO: 76, and a CDR3-H of sequence SEQ ID NO: 81 , and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLLKPGQSPQLLIYKVSNR FSGISDRFSGGGSGTDFTLKISRLEPDDLGIYYCGQGTQYPFTFGSGTKLEIK (SEQ ID NO: 82, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "16F8-A7" anti-CD3 antibody comprises:

a heavy chain variable domain comprising the sequence VETGGNLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNNYATY YAESVKGRFTISRDDSKSSVYLQMNSLKEEDTAIYYCRYVNYGLAPMDVWGQGTSVTV SS (SEQ ID NO: 83, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 84, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQLLIYKVSN

RFSGFSDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 85, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "1 1 F9-F8" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGTLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSKTSVYLQLNSLREEDTAIYYCRGTQYGYNPFDYWGQGV MVTVSS (SEQ ID NO: 46, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 47, and

a light chain variable domain consisting of sequence DVVLTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWSLQKPGQSPQVLIYKVSNR FSGISNRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGAHYPFTFGSGTKLEIK (SEQ ID NO: 87, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 88.

The so-called "3G5-E10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVKLVESGGGLVQPGRSLKLSCAASGFNFNVYWMGVWRQAPGKGLEWIGEIKKDSNSI NYTPSLKEKFTISRDNAQNTLYLQVNKLGSEDTAIYYCAREERDGYFDYWGQGVMVTVS

S (SEQ ID NO: 89, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 90, a CDR2-H of sequence SEQ ID NO: 91 , and a CDR3-H of sequence SEQ ID NO: 32, and

a light chain variable domain consisting of sequence NIVMTQSPKSMSMSVGERVTLTCKASENWTYVSWYQQKPEQSPKLLIYGASNRYTGV PDRFTGSGSATDFTLTISSVQAEDLADYHCGQGYSYPYTFGGGTKLEIK (SEQ ID NO: 92, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 93, a CDR2-L consisting of sequence 'GAS', and a CDR3-L of sequence SEQ ID NO: 94.

The so-called "9D7-F3" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence AVQLVESGGGLVQPKESLKISCAASGFTFSNAAMYWVRQAPGKGLEVWARIRTKPNNY ATYYADSVTGRFIISRDDSRSMVYLQMDNLQTEDTAMYYCTALISTAMAAWGQGTSVT VSS (SEQ ID NO: 95, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 96, a CDR2-H of sequence SEQ ID NO: 97, and a CDR3-H of sequence SEQ ID NO: 98, and

a light chain variable domain consisting of sequence DIQMTQSPSFLSASVGDRVTINCKASQNINKYLNWYHQMLGEAPKLVISNTNNLQAGIPS RFSGSGSGTDFTLTISSLQPEDVATYFCLQHRSGYTFGLGTKLELK (SEQ ID NO: 99, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 100, a CDR2-L consisting of sequence 'NTN', and a CDR3-L of sequence SEQ ID NO: 101.

The so-called "8C2-F7" anti-CD3 antibody comprises:

- a heavy chain variable domain consisting of sequence QIQLVQSGPELKKPGESVKISCKASGYTFTDFAMNWVKQAPGNGLKWMGWINTQTGK PTYADGFKQRFVFSLETSASTIYLQINNLNIEDTATYFCTRGALASVGQGVLVTVSS

(SEQ ID NO: 102, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 103, a CDR2-H of sequence SEQ ID NO: 104, and a CDR3-H of sequence SEQ ID NO: 105, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGSHVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQPLIYKVSN RFSGISDRFSGSGSGTDFTLEINRVEPDDLGVYYCGQGAQYPFTFGSGTKLEIK (SEQ ID NO: 106, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "20E5-F10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGENLVQPGKSLRLTCATSGFSFSNAWMHWIRQSPEKQLEVWAQIKDKSNNY ATYYAESVNGRFTISRDDSKSSIYLHMDNLKEEDSAIYYCRYVHYGVRFFYTMDVWGQG TSVTVSS (SEQ ID NO: 107, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 80, a CDR2-H of sequence SEQ ID NO: 19, and a CDR3-H of sequence SEQ ID NO: 108, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGDQVSISCRPSQSLVHNNGNTYLSWYLQKPGQSPHPLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGSGTKLEIK (SEQ ID NO: 109, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "20B5-F10" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGSLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKAKSNN YATYYAESVKGRFTISRDDSISSVYLQMNNLKEEDTAIYYCRGVYYGFLGMDAWGQGT SVTVSS (SEQ ID NO: 1 10, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 37, and a CDR3-H of sequence SEQ ID NO: 1 1 1 , and

- a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQRLVHNNGNTYLSWYLQKPGQSPQLLVYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTEYPFTFGSGTKLEIK (SEQ ID NO: 1 12, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 1 13, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 14.

The so-called "6C9-C9" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence AVQLVESGGGLVRPKESLKISCAASGFTFRNAAMYWVRQAPGKGLEVWARIRTQPNNY AKYYADSVKDRFTISRDDSKSMVYLQMDNLKTEDTAMYYCTGLWTAMDAWGQGTSV TVSS (SEQ ID NO: 1 15, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 1 16, a CDR2-H of sequence SEQ ID NO: 1 17, and a CDR3-H of sequence SEQ ID NO: 1 18, and

a light chain variable domain consisting of sequence DIQMTQSPSFLSASVGDRVTINCKASQNINKYLNWYQQKLGEAPKLLIYVTNNLQTGIPS RFSGSGSGTDYTLTISSLQPEDVATYFCLQHRSMYTFGTGTKLELK (SEQ ID NO: 1 19, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 100, a CDR2-L consisting of sequence 'VTN', and a CDR3-L of sequence SEQ ID NO: 120.

The so-called "3E8-G1 " anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQVVESGGGLVQPGRSLKLSCAASGFTFSNYYMDWVRQAPKKGLEVWATITASGSRI YYPDSVKGRFTISRDNAKSSLYLLMNSLKSEDTATYYCARERTDAYFDYWGQGVMVTV SS (SEQ ID NO: 121 , with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 122, a CDR2-H of sequence SEQ ID NO: 123, and a CDR3-H of sequence SEQ ID NO: 124, and

a light chain variable domain consisting of sequence QFILTQPNSVSTILGSTVKLSCKRSTGNIGTNYVSWYQHHEGRSPTTMIYRDDKRPDGV PDRFSGSIDRSSNSALLTINNVQTEDEADYFCQSYISGLNPVFGGGSKLTVL (SEQ ID NO: 125, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 126, a CDR2-L consisting of sequence 'RDD', and a CDR3-L of sequence SEQ ID NO: 127.

The so-called "3H6-D2" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence EVQLVETGGRLVQPGKSLKLTCATSGFTFSNAWMHVWRQSPEKQLEVWAQIKDKSNN YATYYAESVKGRFTISRDDSKSIIYLQMNSLKEEDTAIYYCRALTYYGYKRDAMDGWGH GTSVTVSS (SEQ ID NO: 128, with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 13, a CDR2-H of sequence SEQ ID NO: 19, and a CDR3-H of sequence SEQ ID NO: 129, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVSLGGQVSISCRSSQSLVHNNGNTYLSWYLQKPGQSPQLLIYKVSN RFSGISDRFSGSGSGTDFTLKISRVEPDDLGVYYCGQGTQYPFTFGAGTKLELK (SEQ ID NO: 130, with CDRs shown in bold characters and underlined) comprising CDR1 -L of sequence SEQ ID NO: 10, a CDR2-L consisting of sequence 'KVS', and a CDR3-L of sequence SEQ ID NO: 1 1.

The so-called "8H2" anti-CD3 antibody comprises:

a heavy chain variable domain consisting of sequence QIQLVQSGPELKKPGESVKISCKASGYTFTDFAMNWVKQAPGNGLKWMGWINTQTGK PTYADGFKQRFVFSLETSASTIYLQINNLNIEDTATYFCTRGALASVGQGVMVTVSS

(SEQ ID NO: 131 , with CDRs shown in bold characters and underlined) comprising CDR1-H of sequence SEQ ID NO: 103, a CDR2-H of sequence SEQ ID NO: 104, and a CDR3-H of sequence SEQ ID NO: 105, and

a light chain variable domain consisting of sequence DVVMTQTPVSLSVAIGQPASISCKSSQSLVGTSGKTYLNWLLQRPGQSPKRLIYLVSKLD SGIPDRFSGSGSETDFTLKISRVETDDLGVYYCLQGSHFPLTFGSGTKLEIK (SEQ ID NO: 132, with CDRs shown in bold characters and underlined) comprising CDR1-L of sequence SEQ ID NO: 133, a CDR2-L consisting of sequence 'LVS', and a CDR3-L of sequence SEQ ID NO: 134.

In an embodiment, the anti-CD3 antibody of the invention binds to human CD3. In another embodiment, the anti-CD3 antibody of the invention further binds to Macaca fascicularis CD3. In particular, the anti-CD3 antibody of the invention binds to the extracellular domain of human CD3, or of both human and Macaca fascicularis CD3. More specifically, the antibody binds to CD3£. More specifically, the anti-CD3 antibody binds to the human and Macaca fascicularis extracellular domain of CD3£. The anti-CD3 antibody binds to CD3£ when present in the form of a complex, such as a CD3£/5 complex, or when present as single protein, indifferently whether expressed in isolated form, or present in a soluble extracellular domain or full-length membrane-anchored CD3£ as present in for example in T-cells.

The anti-CD3 antibody according to the invention is specific for the surface human CD3 protein, or of both human and Macaca fascicularis CD3 proteins, in particular to CD3£.

In an embodiment, the anti-CD3 antibody according to the invention has a ratio of affinity for Macaca fascicularis CD3 on affinity for human CD3 (KD(Macaca fascicularis)/ KD(human)) which is <10, in particular <6, <5, <4, <3, for example <2, <1 or <0.5. Such a polypeptide according to the invention may be used in toxicological studies performed in monkeys the toxicity profile observed in monkeys relevant to anticipate potential adverse effects in humans

In particular, the anti-CD3 antibody of the invention does not bind to, or does not significantly cross-react with CD3y and/or CD35 protein(s).

In particular, the antibody does not bind to, or does not significantly cross-react with the extracellular domain of the aforementioned human and Macaca fascicularis CD3y and/or CD35 protein(s).

The sequence of full-length human CD35 protein is available in Uniprot database under accession number P04234 (SEQ ID NO: 86, as available on December 14, 2014). The extracellular domain of human CD35 consists of amino acids at positions 22-105 of SEQ ID NO: 86.

The sequence of full-length human CD3y protein is available in Uniprot database under accession number P09693 (SEQ ID NO: 185, as available on December 14, 2014). The extracellular domain of human CD3y consists of amino acids at positions 23-116 of SEQ ID NO: 185.

Furthermore, the anti-CD3 antibody according to the invention has an affinity (KD) for human CD3 or Macaca fascicularis CD3, or both, which is <90nM, <50nM, or <30nM, for instance < 20nM, < 10nM, < 8nM, < 6nM, < 4nM or <2nM, for instance an affinity of 0.1 nM to 10 nM, in particular of 0.1 nM to 8 nM, or of 0.1 nM to 4 nM.

Affinity for human CD3 or for Macaca fascicularis CD3 is determined as the KD value with surface plasmon resonance using soluble recombinant CD3£/5 complex from human and Macaca fascicularis as capture antigen.

In one example, binding affinities of an anti-CD3 antibody is measured by surface plasmon resonance (SPR) using for instance a Biacore3000 instrument (GE Healthcare). Assay buffer is for example HBS-EP (BR-1001 -88, GE Healthcare). As antigen may be used, for example, the human CD3£ and human CD35 subunit extracellular domain constructs, including the signal peptide, in form of Fc-fusion proteins as described in the examples. Alternatively, use may be made, as antigen, of the Macaca fascicularis CD3£ and Macaca fascicularis CD35 subunit extracellular domain constructs, including the signal peptide, in form of Fc-fusion proteins as described in the examples. Capture of human or Macaca fascicularis CD3£/5-Fc fusion proteins is achieved using, for example, the human antibody capture kit (GE Healthcare). For example, the capture antibody may be coupled to CM5 chips (BR-1001-88, GE Healthcare) to for instance approx. 12.000 RU using for example the amine coupling kit (BR-100-50, GE Healthcare). The CD3£/5-Fc fusions proteins are captured at 10 μΙ/min to approx. 70 RU to yield Rmax values of 30 RU. Binding kinetics for an anti-CD3 antibody may be measured at, for example, 30 μΙ/min for 240 s and 600 s. for association and dissociation phase, respectively. For example, two fold dilutions of an anti-CD3 antibody from 3 to 400 nM in assay buffer may be used. Regeneration of the capture surface may be performed with for example a 1 min injection of for instance 3M MgCI2 solution at 30 μΙ/min. For data analysis for example the BIAevaluation software v.4.1 (GE Healthcare) may be used. Data may be fit globally using a 1 :1 Langmuir model with mass transfer.

In an embodiment, the anti-CD3 antibody of the invention also has an apparent EC50 as, for example, determined by FACS analysis on human T-cells, which is <60nM, for instance <50nM, <40nM, <30nM, <20nM or <15nM. Typically, the apparent EC50 is within the range 1 to 60 nM, in particular 1 to 30nM, for example 1 to 20nM.

In one embodiment, the anti-CD3 antibody of the invention has a T-cell activation that is less than 10%, less than 8%, less than 6%, less than 4%, less than 2%, less than 1 %, for example less than 0.5% in the absence of target cells.

The term "activation of T-cells" herein refers to triggering CD3 signaling involving cytotoxic granule fusion, transient cytokine release, and proliferation. The antibody-like binding protein and the anti-CD3 antibody of the invention target CD3£ and activate T-cells in the presence of target cells; this activity is also referred to as a "T-cell engaging effect". The T-cell engaging effect induces cytotoxicity in the target cell.

As known by the skilled in the art, activation of T-cells induces the expression of surface marker such as CD69 and CD25. The activation of T-cells can thus be measured by detecting and measuring the expression of CD4+/CD25+, CD4+/CD69+, CD8+/CD25+, or CD8+/CD69+ T cells. Methods to measure T-cell activation are known to the skilled in the art.

A method to measure T-cell activation is further disclosed in the example section (Example 3.3). Accordingly, in context of the invention T-cell activation is measured either as the percentage of cells expressing CD69 in % of the total number of cells, or as the percentage of cells expressing CD4 andCD69 in % of total number of cells, or as the percentage of cells expressing CD8 and CD69 in % of the total number of cells.

"Low T-cell activation" in context with the anti-CD3 antibody of the invention refers to less than 10%, less than 8%, less than 6%, less than 4%, less than 2%, less than 1 %, for example less than 0.5% T-cell activation in the absence of target cells.

Alignments of the sequences of the VH and VL regions of the "20G6-F3", "4B4-D7", "4E7-C9", "18F5-H10", "12D2-E5", "1 1 D7-C3", "1 1 H3-E5", "13H2-C2", "13C1 -F6",

"18H1 1 -F10", "1 E6-C9", "10F4-C10", "10E6-G6", "18G9-H1 1 ", "1 1 F3-B9", "12G3-E8", "5B1-G2", "16F8-A7", "1 1 F9-F8", "3G5-E10", "9D7-F3", "8C2-F7", "20E5-F10", "20B5-F10", "6C9-C9", "3E8-G1 ", "3H6-D2" and "8H2" anti-CD3 antibodies were performed. The comparison of the CDR-H and CDR-L sequences tends to indicate that, structurally, "20G6-F3", "4B4-D7", "4E7-C9", "18F5-H10", "1 1 D7-C3", Ί 1 Η3-Ε5", "13H2-C2", "13C1-F6", "1 E6-C9", "10F4-C10", "10E6-G6", "18G9-H11 ", "1 1 F3-B9", "12G3-E8", "5B1 -G2", "16F8-A7", "1 1 F9-F8", "20E5-F10", "20B5-F10" and "3H6-D2" are closely related, said antibodies probably binding to the same epitope. The comparison of the CDR-H and CDR-L sequences of said related antibodies is presented in Figures 1 and 2, respectively. CDR positions were identified that are strictly conserved between the antibodies and which are thus assumed to be important for specificity, whereas other positions could support substitution.

Accordingly, the antibody according to the invention comprises:

a heavy chain variable domain comprising a CDR1-H consisting of sequence GFX1X2X3X4AW (SEQ ID NO: 331 ) wherein X·, is T or S, X2 is F or V, X3 is S or T and X4 is N, K, L or Y, or any combination thereof; and

a CDR2-H consisting of sequence IKX1X2X3NX4YX5T (SEQ ID NO: 332) wherein X·, is A or D, X2 is K or R, X3 is S or A, X4 is N or S and X5 is A or E, or any combination thereof; and

a CDR3-H consisting of sequence TWRHYYSSHTMDA (SEQ ID NO: 69) or

RALTYYG YKRDAM DG (SEQ ID NO: 129) or RX1X2X3YX4X5X6X7X8X9XioXii DX12 (SEQ ID NO: 333) wherein X! is Y, G or A, X2 is V, T or L, X3 is H, N, Y or Q, X4 is G, R or A, X5 is F or V or no amino acid, X6 is R or no amino acid, X7 is F, S or I or no amino acid, X8 is F, L, N, M, Y, S, A or G, X9 is Y, A, K, S, N, T, F or L, X10 is A, P, G or T, X-π is M, L, F or S and ΧΊ2 is A, V or Y, or any combination thereof, and a light chain variable domain comprising a CDR1 -L consisting of sequence QX1LX2HX3NGX4TY (SEQ ID NO: 334) wherein X! is R or S, X2 is V or E, X3 is N, D or T, and X4 is N or Y, or any combination thereof; and

a CDR2-L consisting of sequence 'KVS'; and

a CDR3-L consisting of sequence GQGXiX2YPFT (SEQ ID NO: 335) wherein Xi is T, A or S and X2 is H, E or Q, or any combination thereof.

According to an embodiment, the anti-CD3 antibody according to the invention comprises the CDR sequences of the heavy and/or light chains of one of 28 so-called

"20G6-F3", "4B4-D7", "4E7-C9", "18F5-H10", "12D2-E5", "1 1 D7-C3", Ί 1 Η3-Ε5", "13H2-C2", "13C1 -F6", "18H1 1-F10", "1 E6-C9", "10F4-C10", "10E6-G6", "18G9-H1 1 ", "1 1 F3-B9", "12G3-E8", "5B1-G2", "16F8-A7", "1 1 F9-F8", "3G5-E10", "9D7-F3", "8C2-F7", "20E5-F10", "20B5-F10", "6C9-C9", "3E8-G1 ", "3H6-D2" and "8H2" anti-CD3 antibodies listed above.

Therefore, the invention relates to an anti-CD3 antibody, which comprises:

a) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 6 or a sequence differing from SEQ ID NO: 6 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 7 or a sequence differing from SEQ ID NO: 7 by one or more amino acid substitution; CDR3-H of sequence SEQ ID NO: 8 or a sequence differing from SEQ ID NO: 8 by one amino acid substitution; and a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 10 or SEQ ID NO: 142 or a sequence differing from SEQ ID NO: 10 or SEQ ID NO: 142 by one amino acid substitution substitution; CDR2-L of sequence VS' or a sequence differing from the sequence KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

b) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 14 or a sequence differing from SEQ ID NO:

14 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

15 or a sequence differing from SEQ ID NO: 15 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17 or SEQ ID NO: 184 or a sequence differing from SEQ ID NO: 17 or SEQ ID NO: 184 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

c) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 19 or a sequence differing from SEQ ID NO: 19 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

20 or a sequence differing from SEQ ID NO: 20 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 22 or a sequence differing from SEQ ID NO: 22 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 24 or a sequence differing from SEQ ID NO: 24 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 19 or a sequence differing from SEQ ID NO: 19 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 25 or a sequence differing from SEQ ID NO: 25 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 27 or a sequence differing from SEQ ID NO: 27 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 28 or a sequence differing from SEQ ID NO: 28 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 30 or a sequence differing from SEQ ID NO: 30 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 31 or a sequence differing from SEQ ID NO:

31 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

32 or a sequence differing from SEQ ID NO: 32 by one amino acid substitution; and

a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 34 or a sequence differing from SEQ ID NO: 34 by one amino acid substitution; CDR2-L of sequence 'RDD' or a sequence differing from the sequence 'RDD' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 35 or a sequence differing from SEQ ID NO: 35 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 38 or a sequence differing from SEQ ID NO: 38 by one amino acid substitution; and

a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 28 or a sequence differing from SEQ ID NO: 28 by one amino acid substitution; or

g) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO:

37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 41 or a sequence differing from SEQ ID NO: 41 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17 or a sequence differing from SEQ ID NO: 17 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

h) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution;

CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 44 or a sequence differing from SEQ ID NO: 44 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 11 by one amino acid substitution; or

i) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 47 or a sequence differing from SEQ ID NO: 47 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 50 or a sequence differing from SEQ ID NO: 50 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 51 or a sequence differing from SEQ ID NO:

51 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

52 or a sequence differing from SEQ ID NO: 52 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 54 or a sequence differing from SEQ ID NO: 54 by one amino acid substitution; CDR2-L of sequence 'NAN' or a sequence differing from the sequence 'NAN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 55 or a sequence differing from SEQ ID NO: 55 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 57 or a sequence differing from SEQ ID NO: 57 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 58 or a sequence differing from SEQ ID NO: 58 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 28 or a sequence differing from SEQ ID NO: 28 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 61 or a sequence differing from SEQ ID NO: 61 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

m) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 64 or a sequence differing from SEQ ID NO: 64 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 65 or a sequence differing from SEQ ID NO:

65 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 47 or a sequence differing from SEQ ID NO: 47 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 67 or a sequence differing from SEQ ID NO: 67 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 28 or a sequence differing from SEQ ID NO: 28 by one amino acid substitution; or

n) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution;

CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 69 or a sequence differing from SEQ ID NO: 69 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 71 or a sequence differing from SEQ ID NO: 71 by one amino acid substitution; or

o) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 84 or a sequence differing from SEQ ID NO: 84 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17 or a sequence differing from SEQ ID NO: 17 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 75 or a sequence differing from SEQ ID NO: 75 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 76 or a sequence differing from SEQ ID NO:

76 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

77 or a sequence differing from SEQ ID NO: 77 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 80 or a sequence differing from SEQ ID NO: 80 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 76 or a sequence differing from SEQ ID NO: 76 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 81 or a sequence differing from SEQ ID NO: 81 by one amino acid substitution; and

a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO: 37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 84 or a sequence differing from SEQ ID NO: 84 by one amino acid substitution; and

a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

s) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13 or a sequence differing from SEQ ID NO: 13 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 37 or a sequence differing from SEQ ID NO:

37 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 47 or a sequence differing from SEQ ID NO: 47 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 88 or a sequence differing from SEQ ID NO: 88 by one amino acid substitution; or

t) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 90 or a sequence differing from SEQ ID NO: 90 by one amino acid substitution;

CDR2-H of sequence SEQ ID NO: 91 or a sequence differing from SEQ ID NO: 91 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 32 or a sequence differing from SEQ ID NO: 32 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 93 or a sequence differing from SEQ ID NO: 93 by one amino acid substitution; CDR2- L of sequence 'GAS' or a sequence differing from the sequence 'GAS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 94 or a sequence differing from SEQ ID NO: 94 by one amino acid substitution; or

u) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 96 or a sequence differing from SEQ ID NO: 96 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 97 or a sequence differing from SEQ ID NO: 97 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 98 or a sequence differing from SEQ ID NO: 98 by one amino acid substitution; and

a light chain variable domain comprising CDR1-L of sequence SEQ ID NO: 100 or a sequence differing from SEQ ID NO: 100 by one amino acid substitution; CDR2-L of sequence 'NTN' or a sequence differing from the sequence 'NTN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 101 or a sequence differing from SEQ ID NO: 101 by one amino acid substitution; or v) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO:

103 or a sequence differing from SEQ ID NO: 103 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 104 or a sequence differing from

SEQ ID NO: 104 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 105 or a sequence differing from SEQ ID NO: 105 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

w) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 80 or a sequence differing from SEQ ID NO: 80 by one amino acid substitution;

CDR2-H of sequence SEQ ID NO: 19 or a sequence differing from SEQ ID NO: 19 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 108 or a sequence differing from SEQ ID NO: 108 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2- L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by

****
CLAIMS

1 . An isolated antibody that binds to the extracellular domain of human CD3e protein comprising:

a) a heavy chain variable domain comprising a CDR1 -H consisting of sequence

GFX1X2X3X4AW (SEQ ID NO: 331 ) wherein X, is T or S, X2 is F or V, X3 is S or T and X4 is N, K, L or Y, or any combination thereof; and

a CDR2-H consisting of sequence IKX1X2X3NX4YX5T (SEQ ID NO: 332) wherein X^ is A or D, X2 is K or R, X3 is S or A, X4 is N or S and X5 is A or E, or any combination thereof; and

a CDR3-H consisting of sequence TWRHYYSSHTMDA (SEQ ID NO: 69) or RALTYYGYKRDAMDG (SEQ ID NO: 129) or RX1X2X3YX4X5X6X7X8X9XioXii DX12 (SEQ ID NO: 333) wherein X, is Y, G or A, X2 is V, T or L, X3 is H, N, Y or Q, X4 is G, R or A, X5 is F or V or no amino acid, X6 is R or no amino acid, X7 is F, S or I or no amino acid, X8 is F, L, N, M, Y, S, A or G, X9 is Y, A, K, S, N, T, F or L, X10 is A, P, G or T, Xn is M, L, F or S and Xi2 is A, V or Y, or any combination thereof, and a light chain variable domain comprising a CDR1 -L consisting of sequence

QX1LX2HX3NGX4TY (SEQ ID NO: 334) wherein X, is R or S, X2 is V or E, X3 is N, D or

T, and X4 is N or Y, or any combination thereof; and

a CDR2-L consisting of sequence 'KVS'; and

a CDR3-L consisting of sequence GQGXiX2YPFT (SEQ ID NO: 335) wherein Xi is T,

A or S and X2 is H, E or Q, or any combination thereof; or

a) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 30 or a sequence differing from SEQ ID NO: 30 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 31 or a sequence differing from SEQ ID NO: 31 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 32 or a sequence differing from SEQ ID NO: 32 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 34 or a sequence differing from SEQ ID NO: 34 by one amino acid substitution; CDR2-L of sequence 'RDD' or a sequence differing from the sequence 'RDD' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 35 or a sequence differing from SEQ ID NO: 35 by one amino acid substitution; or

b) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 50 or a sequence differing from SEQ ID NO: 50 by one amino acid substitution; CDR2-H of

sequence SEQ ID NO: 51 or a sequence differing from SEQ ID NO: 51 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 52 or a sequence differing from SEQ ID NO: 52 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 54 or a sequence differing from SEQ ID NO: 54 by one amino acid substitution; CDR2-L of sequence 'NAN' or a sequence differing from the sequence 'NAN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 55 or a sequence differing from SEQ ID NO: 55 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 90 or a sequence differing from SEQ ID NO: 90 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 91 or a sequence differing from SEQ ID NO: 91 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 32 or a sequence differing from SEQ ID NO: 32 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 93 or a sequence differing from SEQ ID NO: 93 by one amino acid substitution; CDR2-L of sequence 'GAS' or a sequence differing from the sequence 'GAS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 94 or a sequence differing from SEQ ID NO: 94 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 96 or a sequence differing from SEQ ID NO: 96 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 97 or a sequence differing from SEQ ID NO: 97 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 98 or a sequence differing from SEQ ID NO: 98 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 100 or a sequence differing from SEQ ID NO: 100 by one amino acid substitution; CDR2-L of sequence 'NTN' or a sequence differing from the sequence 'NTN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 101 or a sequence differing from SEQ ID NO: 101 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 103 or a sequence differing from SEQ ID NO: 103 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 104 or a sequence differing from SEQ ID NO: 104 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 105 or a sequence differing from SEQ ID NO: 105 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or a sequence differing from SEQ ID NO: 10 by one amino acid substitution; CDR2-L of sequence 'KVS' or a sequence differing from the sequence 'KVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 1 1 or a sequence differing from SEQ ID NO: 1 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ I D NO: 1 16 or a sequence differing from SEQ ID NO: 1 16 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 1 17 or a sequence differing from SEQ ID NO: 1 17 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 1 18 or a sequence differing from SEQ ID NO: 1 18 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 100 or a sequence differing from SEQ ID NO: 100 by one amino acid substitution; CDR2-L of sequence VTN' or a sequence differing from the sequence VTN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 120 or a sequence differing from SEQ ID NO: 120 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ I D NO: 122 or a sequence differing from SEQ ID NO: 122 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 123 or a sequence differing from SEQ ID NO: 123 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 124 or a sequence differing from SEQ ID NO: 124 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 126 or a sequence differing from SEQ ID NO: 126 by one amino acid substitution; CDR2-L of sequence 'RDD' or a sequence differing from the sequence 'RDD' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 127 or a sequence differing from SEQ ID NO: 127 by one amino acid substitution.

2. The isolated antibody according to claim 1 , comprising:

a) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 6,

CDR2-H of sequence SEQ ID NO: 7, CDR3-H of sequence SEQ ID NO: 8 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10 or SEQ ID NO: 142, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or

b) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 14, CDR3-H of sequence SEQ ID NO: 15 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17 or SEQ ID NO: 184, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or

c) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 19, CDR3-H of sequence SEQ ID NO: 20 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 22, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or d) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 24,

CDR2-H of sequence SEQ ID NO: 19, CDR3-H of sequence SEQ ID NO: 25 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 27, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 28; or e) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 30, CDR2-H of sequence SEQ ID NO: 31 , CDR3-H of sequence SEQ ID NO: 32 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 34, CDR2-L of sequence 'RDD' and CDR3-L of sequence SEQ ID NO: 35; or f) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 38 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10,

CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 28; or g) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 41 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or h) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 44 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or i) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 47 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or j) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 50, CDR2-H of sequence SEQ ID NO: 51 , CDR3-H of sequence SEQ ID NO: 52 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 54, CDR2-L of sequence 'NAN' and CDR3-L of sequence SEQ ID NO: 55; or k) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 57, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 58 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 28; or

I) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 61 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10,

CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or m)a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 64, CDR2-H of sequence SEQ ID NO: 65, CDR3-H of sequence SEQ ID NO: 47 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 67, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 28; or n) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 69 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 71 ; or o) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13,

CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 84 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 17, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or p) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 75, CDR2-H of sequence SEQ ID NO: 76, CDR3-H of sequence SEQ ID NO: 77 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or q) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 80, CDR2-H of sequence SEQ ID NO: 76, CDR3-H of sequence SEQ ID NO: 81 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10,

CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or r) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 84 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or s) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 47 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 88; or

t) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 90, CDR2-H of sequence SEQ ID NO: 91 , CDR3-H of sequence SEQ ID NO: 32 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 93, CDR2-L of sequence 'GAS' and CDR3-L of sequence SEQ ID NO: 94; or u) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 96,

CDR2-H of sequence SEQ ID NO: 97, CDR3-H of sequence SEQ ID NO: 98 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 100, CDR2-L of sequence 'NTN' and CDR3-L of sequence SEQ ID NO: 101 ; or v) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 103, CDR2-H of sequence SEQ ID NO: 104, CDR3-H of sequence SEQ ID NO: 105 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or w) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 80, CDR2-H of sequence SEQ ID NO: 19, CDR3-H of sequence SEQ ID NO: 108 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10,

CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or x) a heavy chain variable domain comprising CDR1-H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 37, CDR3-H of sequence SEQ ID NO: 1 1 1 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 1 13, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 14; or y) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 1 16, CDR2-H of sequence SEQ ID NO: 1 17, CDR3-H of sequence SEQ ID NO: 1 18 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 100, CDR2-L of sequence 'VTN' and CDR3-L of sequence SEQ ID NO: 120; or z) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 122,

CDR2-H of sequence SEQ ID NO: 123, CDR3-H of sequence SEQ ID NO: 124 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 126, CDR2-L of sequence 'RDD' and CDR3-L of sequence SEQ ID NO: 127; or aa) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 13, CDR2-H of sequence SEQ ID NO: 19, CDR3-H of sequence SEQ ID NO: 129 and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 10, CDR2-L of sequence 'KVS' and CDR3-L of sequence SEQ ID NO: 1 1 ; or bb) a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 103, CDR2-H of sequence SEQ ID NO: 104, CDR3-H of sequence SEQ ID NO: 105; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 133, CDR2-L of sequence 'LVS' and CDR3-L of sequence SEQ ID NO: 134.

3. An antibody-like binding protein that binds specifically to human CD3e comprising two polypeptide chains that form two antigen-binding sites, wherein a first polypeptide has a structure represented by the formula [I]:

VD1-L VD2-L2-CL [I] and a second polypeptide has a structure represented by the formula [II]:

VD3-L3-VD4-L4-CHI [II] wherein:

VD1 is a variable domain of heavy or light chain of a first immunoglobulin;

VD2 is a variable domain of heavy or light chain of a second immunoglobulin;

VD3 is a variable domain of heavy or light chain of said second immunoglobulin;

VD4 is a variable domain of heavy or light chain of said first immunoglobulin;

C|_ is a light chain constant domain of an immunoglobulin;

Cm is a C HI heavy chain constant domain of an immunoglobulin;

U, l_2, L3, and L4 are amino acid linkers;

and wherein the first and the second polypeptide form a cross-over light chain-heavy chain pair, and

wherein the VD1 and VD4, or VD2 and VD3 comprise a heavy chain variable domain and a light chain variable domain of an antibody as defined in claim 1 .

4. The antibody like binding protein according to claim 3, wherein the polypeptide of formula [II] further comprises a FC domain.

5. The antibody like binding protein according to claim 3 or 4, comprising two polypeptide chains that form two antigen-binding sites, wherein one polypeptide chain has a structure represented by the formula [I]:

VD1-L VD2-L2-CL [I] and one polypeptide chain has a structure represented by the formula [III]:

VD3-L3-VD4-L4-CHI-Fc [III] wherein:

VD1 is a variable domain of heavy or light chain of a first immunoglobulin;

VD2 is a variable domain of heavy or light chain of a second immunoglobulin;

VD3 is a variable domain of heavy or light chain of said second immunoglobulin;

VD4 is a variable domain of heavy or light chain of said first immunoglobulin;

C|_ is a light chain constant domain of an immunoglobulin;

Cm is a C HI heavy chain constant domain of an immunoglobulin;

FC is the immunoglobulin hinge region and CH2, CH3 immunoglobulin heavy chain constant domains of an immunoglobulin;

U, l_2, L3, and L4 are amino acid linkers;

and wherein the polypeptide formula I and the polypeptide of formula I I I form a cross-over light chain-heavy chain pair, and

wherein the VD1 and VD4, or VD2 and VD3 comprise a heavy chain variable domain and a light chain variable domain of an antibody as defined in claim 1.

6. The antibody like binding protein according to claim 4 or 5, wherein the polypeptide of formula [I] further comprises a FC domain (FC2).

7. The antibody like binding protein according to any one of claims 4 to 6, comprising two polypeptide chains that form two antigen-binding sites, wherein one polypeptide chain has a structure represented by the formula [IV]:

VD1-L VD2-L2-CL-L5-FC2 [IV] and one polypeptide chain has a structure represented by the formula [I I I]:

VD3-L3-VD4-L4-CHI-FC [I I I] wherein:

VD1 is a variable domain of heavy or light chain of a first immunoglobulin;

VD2 is a variable domain of heavy or light chain of a second immunoglobulin;

VD3 is a variable domain of heavy or light chain of said second immunoglobulin;

VD4 is a variable domain of heavy or light chain of said first immunoglobulin;

C|_ is a light chain constant domain of an immunoglobulin;

Cm is a C HI heavy chain constant domain of an immunoglobulin;

FC is the immunoglobulin hinge region and CH2, CH3 immunoglobulin heavy chain constant domains of an immunoglobulin;

FC2 is the immunoglobulin hinge region and CH2, CH3 immunoglobulin heavy chain constant domains of an immunoglobulin;

U, L2, L3, L4 and L5 are amino acid linkers;

wherein the polypeptide of formula [IV] and the polypeptide of formula [I I I] form a crossover light

8. The antibody like binding protein according to claim 4 or 5, which comprises a third polypeptide chain comprising a Fc domain (Fc3).

9. The antibody like binding protein according to any one of claims 4, 5 and 8, comprising three polypeptide chains that form two antigen-binding sites, wherein

a first polypeptide has a structure represented by the formula [I]:

VD1-L VD2-L2-CL [I] a second polypeptide has a structure represented by the formula [I I I]:

VD3-L3-VD4-L4-CHI-FC [I I I] a third polypeptide Fc3 which is the immunoglobulin hinge region and CH2, CH3 immunoglobulin heavy chain constant domains of an immunoglobulin;

wherein

VD1 is a variable domain of heavy or light chain of a first immunoglobulin;

VD2 is a variable domain of heavy or light chain of a second immunoglobulin;

VD3 is a variable domain of heavy or light chain of said second immunoglobulin;

VD4 is a variable domain of heavy or light chain of said first immunoglobulin;

C|_ is a light chain constant domain of an immunoglobulin;

Cm is a C HI heavy chain constant domain of an immunoglobulin;

Fc is the immunoglobulin hinge region and CH2, CH3 immunoglobulin heavy chain constant domains of an immunoglobulin;

Li , L2, L3, and L4 are amino acid linkers;

and wherein the polypeptide of formula [I] and the polypeptide of formula [I I I] form a crossover light chain-heavy chain pair,

wherein the polypeptide of formula [I I I] heterodimerizes with the third polypeptide through its Fc domain; and

wherein the VD1 and VD4, or VD2 and VD3 comprise a heavy chain variable domain and a light chain variable domain of an antibody as defined in claim 1 .

10. The antibody like binding protein according to any one of claims 3 to 9, wherein the antibody-like binding protein binds to at least one further target antigen.

1 1 . The antibody like binding protein according to claim 10, wherein the at least one further antigen target is CD123.

12. The antibody like binding protein according to claim 1 1 , wherein the antibodylike binding protein comprises

a) a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 9 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 308 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 5 or a sequence at least 85% identical thereto, or b) light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 21 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 308 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 18 or a sequence at least 85% identical thereto, or

c) a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 16 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 308 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO 12 or a sequence at least 85% identical thereto, or d) a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 26 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 308 or a sequence at least 85% identical thereto, a heavy chain variable domain the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 23 or a sequence at least 85% identical thereto, or

a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 308 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 143 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 138 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, or

a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 158 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 308 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 312 or a sequence at least 85% identical thereto, and a heavy chain variable domain of a first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 171 or a sequence at least 85% identical thereto, a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 230 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 158 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 171 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4) consisting of the amino acid sequence SEQ ID NO : 226 or a sequence at least 85% identical thereto,

a light chain variable domain of a first immunoglobulin (VD1) consisting of the amino acid sequence SEQ ID NO: 385 or a sequence at least 85% identical thereto, a light chain variable domain of a second immunoglobulin (VD2) consisting of the amino acid sequence SEQ ID NO : 141 or a sequence at least 85% identical thereto, a heavy chain variable domain of the second immunoglobulin (VD3) consisting of the amino acid sequence SEQ ID NO : 138 or a sequence at least 85% identical thereto, and a heavy chain variable domain of the first immunoglobulin (VD4)

consisting of the amino acid sequence SEQ ID NO : 383 or a sequence at least 85% identical thereto.

13. The antibody like binding molecule according to claim 3, which comprises:

a) one polypeptide according to formula [I] consisting of the amino acid sequence

SEQ ID NO: 388 which comprises VD1 of sequence SEQ ID NO: 385, U of sequence SEQ ID NO: 389, VD2 of sequence SEQ ID NO: 141 , L2 of sequence SEQ ID NO: 389 and CL of sequence SEQ ID NO: 310, or

a sequence at least 85% identical to SEQ ID NO: 388 in which the 3 CDRs of sequences SEQ ID NO: 378, 'WAS' and SEQ ID NO: 379 of VD1, and the 3 CDRs of sequences SEQ

ID NO:142, 'KVS' and SEQ ID NO:1 1 of VD2 are unaltered ; and

b) one polypeptide according to formula [II] consisting of the amino acid sequence

SEQ ID NO: 390 which comprises VD3 of sequence SEQ ID NO: 138, L3 is 0 amino acid,

VD4 of sequence SEQ ID NO: 383, L4 is 0 amino acid and CHi of sequence SEQ ID NO: 313, or

a sequence at least 85% identical to SEQ ID NO: 390 in which the 3 CDRs of sequences SEQ ID NO:381 , SEQ ID NO:384, and SEQ ID NO: 382 of VD4, and the 3 CDRs of sequences SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 of VD3 are unaltered;

and wherein the polypeptide of formula [I] and the polypeptide of formula [II] form a cross-over light chain-heavy chain pair.

14. The antibody like binding molecule according to claim 6 or 7, which comprises: a) one polypeptide according to formula [IV] consisting of the amino acid sequence SEQ ID NO: 391 which comprises VD1 of sequence SEQ ID NO: 385, U of sequence SEQ ID NO: 389, VD2 of sequence SEQ ID NO: 141 , L2 of sequence SEQ ID NO: 389, CL of sequence SEQ ID NO: 310, L5 which contains 0 amino acid, and Fc2 of sequence SEQ ID NO: 392, or

a sequence at least 85% identical to SEQ ID NO: 391 in which the 3 CDRs of sequences SEQ ID NO: 378, 'WAS' and SEQ ID NO: 379 of VD1, and the 3 CDRs of sequences SEQ ID NO:142, 'KVS' and SEQ ID NO:1 1 of VD2 are unaltered; and

b) one polypeptide according to formula [III] consisting of the amino acid sequence SEQ ID NO : 393 which comprises VD3 of sequence SEQ ID NO: 138, L3 is 0 amino acid, VD4 of sequence SEQ ID NO: 383, L4 is 0 amino acid, CHi of sequence SEQ ID NO: 313, and and Fc of sequence SEQ ID NO: 394, or

a sequence at least 85% identical to SEQ ID NO : 393 in which the 3 CDRs of sequences SEQ ID NO:381 , SEQ ID NO:384, and SEQ ID NO: 382 of VD4, and the 3 CDRs of sequences SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 of VD3 are unaltered;,

and wherein the polypeptide of formula [IV] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.

15. The antibody like binding molecule according to claim 8 or 9; which comprises: a) one polypeptide according to formula [I] consisting of the amino acid sequence

SEQ ID NO: 388 which comprises VD1 of sequence SEQ ID NO: 385, U of sequence SEQ ID NO: 389, VD2 of sequence SEQ ID NO: 141 , L2 of sequence SEQ ID NO: 389 and CL of sequence SEQ ID NO: 310, or

a sequence at least 85% identical to SEQ ID NO: 388 in which the 3 CDRs of sequences SEQ ID NO: 378, 'WAS' and SEQ ID NO: 379 of VD1, and the 3 CDRs of sequences SEQ ID NO:142, 'KVS' and SEQ ID NO:1 1 of VD2 are unaltered ; and

b) one polypeptide according to formula [III] consisting of the amino acid sequence

SEQ ID NO : 395 which comprises VD3 of sequence SEQ ID NO: 138, L3 is 0 amino acid, VD4 of sequence SEQ ID NO: 383, L4 is 0 amino acid, CHi of sequence SEQ ID NO: 313, and Fc of sequence SEQ ID NO: 396, or

a sequence at least 85% identical to SEQ ID NO : 395 in which the 3 CDRs of sequences SEQ ID NO:381 , SEQ ID NO:384, and SEQ ID NO: 382 of VD4, and the 3 CDRs of sequences SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 of VD3 are unaltered; and

c) one polypeptide Fc3 which consists of sequence SEQ ID NO : 397, or a sequence at least 85% identical thereto, wherein said Fc3 or the sequence at least 85% identical thereto heterodimerises with the Fc region of the polypeptide according to formula [III]; and

wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.

16. The antibody like binding molecule according to claim 8 or 9; which comprises: a) one polypeptide according to formula [I] consisting of the amino acid sequence

SEQ ID NO: 388 which comprises VD1 of sequence SEQ ID NO: 385, U of sequence SEQ ID NO: 389, VD2 of sequence SEQ ID NO: 141 , L2 of sequence SEQ ID NO: 389 and CL of sequence SEQ ID NO: 310, or

a sequence at least 85% identical to SEQ ID NO: 388 in which the 3 CDRs of sequences SEQ ID NO: 378, 'WAS' and SEQ ID NO: 379 of VD1, and the 3 CDRs of sequences SEQ ID NO:142, 'KVS' and SEQ ID NO:1 1 of VD2 are unaltered ; and

b) one polypeptide according to formula [III] consisting of the amino acid sequence SEQ ID NO: 399 which comprises VD3 of sequence SEQ ID NO: 138, L3 is 0 amino acid, VD4 of sequence SEQ ID NO: 383, L4 is 0 amino acid, C™ of sequence SEQ I D NO: 313, and Fc of sequence SEQ ID NO: 400, or

a sequence at least 85% identical to SEQ ID NO: 399 in which the 3 CDRs of sequences SEQ ID NO:381 , SEQ ID NO:384, and SEQ ID NO: 382 of VD4, and the 3 CDRs of sequences SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8 of VD3 are unaltered; and

c) one polypeptide Fc3 which consists of sequence SEQ ID NO : 398, or a sequence at least 85% identical thereto, wherein said Fc3 or the sequence at least 85% identical thereto heterodimerises with the Fc region of the polypeptide according to formula [III]; and

wherein the polypeptide of formula [I] and the polypeptide of formula [III] form a cross-over light chain-heavy chain pair.

17. An isolated antibody that binds to the extracellular domain of human CD123 protein comprising:

a) a heavy chain variable domain comprising CDR1 -H of sequence SEQ I D NO: 227 or a sequence differing from SEQ ID NO: 227 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 228 or SEQ ID NO:353 or SEQ ID NO: 279, or a sequence differing from SEQ ID NO: 228 or SEQ ID NO:353 or SEQ ID NO: 279 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 229 or a sequence differing from SEQ ID NO: 229 by one amino acid substitution; and a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 231 or a sequence differing from SEQ ID NO: 231 by one amino acid substitution; CDR2- L of sequence 'RDD'or a sequence differing from 'RDD' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 232 or a sequence differing from SEQ ID NO: 232 by one amino acid substitution; or

b) a heavy chain variable domain comprising a CDR1 -H consisting of sequence X1YTFTDX2I (SEQ ID NO: 336) wherein X, is G or A and X2 is H, Y or N, or any combination thereof; and

a CDR2-H consisting of sequence INPYSXiGX2 (SEQ ID NO: 337) wherein X^ is G or D and X2 is T or A, or any combination thereof; and

a CDR3-H consisting of sequence ALNYGSYYAMDA (SEQ ID NO 201 ), and a light chain variable domain comprising a CDR1 -L consisting of sequence

XiDIXzXsN (SEQ ID NO: 338) wherein X, is E or K, X2 is F, H or Y and X3 is N or

S, or any combination thereof; and

a CDR2-L consisting of sequence 'DAN' or 'DAS'; and

a CDR3-L consisting of sequence XiQYNX2YPYT (SEQ ID NO: 339) wherein X^ is H or Q and X2 is I, K or N, or any combination thereof; or

a heavy chain variable domain comprising a CDR1 -H consisting of sequence GFSLTSYXi (SEQ ID NO: 340) wherein X, is H or S; and

a CDR2-H consisting of sequence MWX-iDGDT (SEQ ID NO: 341 ) wherein Xi is S or N; and

a CDR3-H consisting of sequence ARGX1X2X3X4X5X6X7X8X9FX10Y (SEQ ID NO: 342) wherein Xi is D, Y or H, X2 is Y or R, X3 is S or T, X4 is S or P, X5 is Y or no amino acid, X6 is L, I or no amino acid, X7 is Y or no amino acid, X8 is L or no amino acid, X9 is W or no amino acid, X10 is A or D, or any combination thereof, and

a light chain variable domain comprising a CDR1 -L consisting of sequence QSFLSSGDX1X2NY (SEQ ID NO: 343) wherein X, is E or G and X2 is R or K, or any combination thereof; and

a CDR2-L consisting of sequence 'WAS'; and

a CDR3-L consisting of sequence QQYYDTPLT (SEQ ID NO: 253), or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 206 or a sequence differing from SEQ ID NO: 206 by one amino acid substitution CDR2-H of sequence SEQ ID NO: 207 or a sequence differing from SEQ ID NO

207 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO

208 or a sequence differing from SEQ ID NO: 208 by one amino acid substitution and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 210 or a sequence differing from SEQ ID NO: 210 by one amino acid substitution; CDR2-L of sequence 'ETS' or a sequence differing from 'ETS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 21 1 or a sequence differing from SEQ ID NO: 21 1 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 213 or a sequence differing from SEQ ID NO: 213 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 214 or a sequence differing from SEQ ID NO:

214 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

215 or a sequence differing from SEQ ID NO: 215 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 217 or a sequence differing from SEQ ID NO: 217 by one amino acid substitution; CDR2-L of sequence 'NTN' or a sequence differing from 'NTN' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 218 or a sequence differing from SEQ ID NO: 218 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 220 or a sequence differing from SEQ ID NO: 220 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 221 or a sequence differing from SEQ ID NO:

221 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

222 or a sequence differing from SEQ ID NO: 222 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 224 or a sequence differing from SEQ ID NO: 224 by one amino acid substitution; CDR2-L of sequence 'RVS' or a sequence differing from 'RVS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 225 or a sequence differing from SEQ ID NO: 225 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 234 or a sequence differing from SEQ ID NO: 234 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 235 or a sequence differing from SEQ ID NO:

235 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO:

236 or a sequence differing from SEQ ID NO: 236 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 238 or a sequence differing from SEQ ID NO: 238 by one amino acid substitution; CDR2-L of sequence 'GAS' or a sequence differing from 'GAS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 239 or a sequence differing from SEQ ID NO: 239 by one amino acid substitution; or

a heavy chain variable domain comprising CDR1 -H of sequence SEQ ID NO: 241 or a sequence differing from SEQ ID NO: 241 by one amino acid substitution; CDR2-H of sequence SEQ ID NO: 242 or a sequence differing from SEQ ID NO: 242 by one or more amino acid substitutions; CDR3-H of sequence SEQ ID NO: 243 or a sequence differing from SEQ ID NO: 243 by one amino acid substitution; and

a light chain variable domain comprising CDR1 -L of sequence SEQ ID NO: 245 or a sequence differing from SEQ ID NO: 245 by one amino acid substitution; CDR2- L of sequence 'YAS' or a sequence differing from 'YAS' by one amino acid substitution and CDR3-L of sequence SEQ ID NO: 246 or a sequence differing from SEQ ID NO: 246 by one amino acid substitution.

18. An antibody-like binding protein that binds specifically to human CD123 comprising two polypeptide chains that form two antigen-binding sites, wherein a first polypeptide has a structure represented by the formula [I]:

VD1-L VD2-L2-CL [I] and a second polypeptide has a structure represented by the formula [II]:

VD3-L3-VD4-L4-CHI [II] wherein:

VD1 is a variable domain of heavy or light chain of a first immunoglobulin;

VD2 is a variable domain of heavy or light chain of a second immunoglobulin;

VD3 is a variable domain of heavy or light chain of said second immunoglobulin;

VD4 is a variable domain of heavy or light chain of said first immunoglobulin;

C|_ is a light chain constant domain of an immunoglobulin;

Cm is a C HI heavy chain constant domain of an immunoglobulin;

Li, L2, L3, and L4 are amino acid linkers;

and wherein the first and the second polypeptide form a cross-over light chain-heavy chain pair, and

wherein the VD1 and VD4 or VD2 and VD3 comprise a heavy chain variable domain and a light chain variable domain of an antibody as defined in claim 17.

19. A pharmaceutical composition comprising an antibody-like binding protein according to any one of claims 3 to 16 or 18, or an anti-CD123 antibody according to claim 17 or an anti-CD3 antibody according to claim 1 or 2 and a pharmaceutically acceptable carrier.

20. An antibody-like binding protein according to any one of claims 3 to 16 or 18, or an anti-CD123 antibody according claim 17, or an anti-CD3 antibody according claim 1 or a pharmaceutical composition according to claim 19 for use as a medicament.

21 . An antibody-like binding protein according to any one of claims 3 to 16 or 18, or an anti-CD123 antibody according claim 17, or a pharmaceutical composition thereof for use for the treatment of cancer.

22. An anti-CD3 antibody according to claim 1 or 2 or a pharmaceutical composition thereof for use for use in preventing or treating a pathological immune response.

23. An antibody-like binding protein, an antibody or pharmaceutical composition for the use according to claim 21 , wherein the cancer is a haematological cancer.

24. A method of treating or preventing a disease or disorder comprising administering to a subject in need thereof a therapeutically effective amount of an antibody-like binding protein according to any one of claims 3 to 16 or 18, or an anti-CD123 antibody according claim 17, or an anti-CD3 antibody according to claim 1 or 2 or a pharmaceutical composition according to claim 19.

25. An isolated nucleic acid comprising a sequence encoding an antibody-like binding protein according to any one of claims 3 to 16 or 18, an anti-CD123 antibody according to claim 17 or an anti-CD3 antibody according to claim 1 or 2.

26. A host cell which has been transformed by a nucleic acid according to claim 25.

27. A kit comprising comprising at least one antibody according to any one of claims 1 , 2 or 17 at least one antibody-like binding protein according to any one of claims 3 to 16.

28. An antibody according to claim 17 for use for ex vivo or in vivo detecting CD123 expression in biological sample of a subject.

29. The antibody for the use according to claim 28, wherein said antibody is labelled with a detectable molecule or substance.

30. The antibody for the use according to any one of claims 28 to 29, wherein said use is for diagnosing the presence of a cancer in a subject, determining susceptibility of a patient having cancer to a therapeutic agent targeting CD123, or monitoring effectiveness of anti-CD123 cancer therapy or detecting cancer relapse after anti-CD123 cancer therapy.

31 . The antibody for the use according to 30, wherein the anti-CD123 cancer therapy uses or antibody-like binding protein according to any one of claims 3 to 16 or 18 or an anti-CD123 antibody according to claim 17.