DESCRIPTION IMMUNITY INDUCTION AGENT TECHNICAL FIELD ,. [0001] The present invention relates to a novel immunity-inducing agent useful as a therapeutic and/or prophylactic agent for cancer. BACKGROUND ART [0002] Cancer is the commonest cause for death among all of the causes for death, and therapies carried out therefor at present are mainly surgical treatment, which may be carried out in combination with radiotherapy and/or chemotherapy. In spite of the developments of new surgical methods and discovery of,new anti-cancer agents in recent years, treatment results of cancers have not been improved very much so far except for some cancers. In recent years, by virtue of the development in molecular biology and cancer immunology, cancer antigens recognized by cytotoxic T cells reactive with cancers, as well as the genes encoding cancer antigens, were identified, and expectations for antigen-specific immunotherapies have been raised. [0003] ln immunotherapy, in order to reduce side effects, the peptide or protein to be recognized as the antigen needs to be hardly present in normal cells, and to be specifically present in cancer cells. In 1991, Boon et al. of Ludwig lnstitute in Belgium isolated a human melanoma antigen MAGE 1, which is recognized by CD8- positive T cells, by a cDNA-expression cloning method using an autologous cancer cell line and cancer-reactive T cells (Non-patent Document 1). Thereafter, the SEREX (serological identifications of antigens by recombinant expression cloning) method, wherein tumor antigens recognized by antibodies produced in the living 15 20 25 f I I; 10 body of a cancer patient in response to the patient's own cancer are identified by application of a gene expression cloning method, was reported (Patent Document 1, Non-patent Document 2), and several cancer antigens have been isolated by this method. Using apfrt of the cancer antigens as targets, clinical tests for cancer immunotherapy have started. [0004] on the other hand, as in human, a number of fumors such as marnmary gland tumor and squamous cell carcinoma are known in dogs and cats, and they rank high also in the statistics of diseases in dogs and cats. However, no therapeutic agent, prophylactic agent or diagnostic agent effective for cancers in dogs or cats exists at present. Since most tumors in dogs and cats are realized by their owners only after the tumors grew larger due to the progression, their visit to the hospital is already too late, and even if they receive surgical excision or administration of a human drug (an anticancer drug or the like), they often die shortly after the teatrnent. Under such circumstances, if therapeutic agents and prophylactic agents for cancer effective for dogs and cats become available, their uses for dog cancers are expected to be developed. [000s] Katanin p60 subunit A-like I (KATNALI) was identified as a protein having a microtubule-binding domain (Patent Document 2, Non-patent Document 3). However, there is no report suggesting that the KATNALI protein has immunityinducing activity against cancer cells and hence that the protein is useful for treatment or prophylaxis of cancer. PRIOR ART DOCUMENTS Patent Documents [0006] [Patent Document U US 5698396 B 15 20 25 ) [Patent Document 2) JP 2004-921,6 A Non-patent Documents [0007] fNon-patent Document 1] Bruggen P. et al., Science, 254:1643-1647 (lggl) 5 [Non-patent Document 2] Proc. Natl. Acad. Sci. USA,92: 11810-11813 (lees) [Non-patent Document 3] Rigden DJ. et al., FEBS Lett., Mar 4; 5g3(5): g72-g (200e) SUMMARY OF THE INVENTION 10 PROBLEMS TO BE SOLVED BY THE INVENTION [0008] The present invention aims to discover a novel polypeptide useful for a therapeutic and/or prophylactic agent for cancer, and to provide the polypeptide for use in an immunity-inducing agent. 15 MEANS FOR SOLVING THE PROBLEMS ' t000el By the sEREx method using a dog testis-derived oDNA library and serum obtained from a tumor-bearing dog, the present inventors intensively studied to obtain a cDNA encoding a protein which binds to antibodies present in serum 20 derived from a tumor-bearing living body, and, based on the cDNA, a polypeptide of dog katanin p60 subunit A-like I (hereinafter referred to as KATNAI.I) having the amino acid sequence of SEQ ID NO:2 was prepared. Further, based on human and mouse homologous genes of the obtained gene, human and mouse KATNAL1 having the amino acid sequences of SEQ ID NOs:4 and 6 were prepared. Further, the 25 present inventors discovered that these KATNAL1 polypeptides are specifically expressed in tissues or cells of breast cancer, brain tumor, perianal adenocarcinoma, neuroblastoma, mastocytoma, liver cancer, prostate cancer, lung cancer, thyroid 3 4 ^1 10 cancer and leukemia. The present inventors further discovered that administration of the KATNAL1 to a living body enables induction of immunocytes against KATNAL1 in the living body and regression of a tumor expressing KATNALI in the living body. Further, the present inventors discovered that arecombinant vector which can express a polynucleotide encoding the I(ATNALI polypeptide or a fragment thereof induces an antitumor effect against cancer expressing I(ATNALI in a living body. [0010] Further, the present inventors discovered that a KATNALI polypeptide has a capacity to be presented by antigen-presenting cells to cause activation and the growth of cytotoxic T cells specific to the peptide (immunity-inducing activity), and therefore that the polypeptide is useful for therapy and/or prophylaxis of cancer. Further, the present inventors discovered that antigen-presenting cells which have contacted with the polypeptide, and T cells which have contacted with the antigenpresenting cells, are useful for therapy and/or prophylaris of cancer, thereby completing the present invention. [001u Thus, the present invention has the following characteristics. (1) An immunity-inducing agent comprising as an effflective ingredient(s) at least one polypeptide having immunity-inducing activity selected from the polypeptides (a) to (c) below, and/or a recombinant vector(s) that comprise(s) a polynucleotide(s) encoding the at least one polypeptide, the recombinant vector(s) being capable of expressing the polypeptide(s) in vivo: (a) a polypeptide composed of not less than 7 consecutive amino acids in any one of the amino acid sequences of SEQ ID NOs:4, 2, 8, 10 and 12 in SEQUENCE LISTING; (b) a polypeptide having a sequence identity of not less than 85% to the 15 20 25 10 polypeptide (a) and composed of not less than 7 amino acids; and (c) a polypeptide comprising the polypeptide (a) or (b) as a partial sequence thereof. (2) The immunity-inducing agent according to (1), wherein the polypeptide having immunity-inducing activity is a polypeptide having the amino acid sequence of SEQ ID NO:4, 2, 8, l0 or 12 in SEQUENCE LISTING. (3) The immunity-inducing agent according to (1) or (2), which is an agent for treating antigen-presenting cells. (4) The immunity-inducing agent according to (1) or (2), which is a therapeutic and/or prophylactic agent for a cancer(s). (5) The immunity-inducing agent according to (4), wherein the cancer(s) is/are a cancer(s) expressing KATNAL1 . (6) The immunity-inducing agent according to (4) or (5), wherein the cancer(s) is/are breast cancer, brain tumor, perianal adenocarcinoma, neuroblastoma, mastocytoma, liver cancer, prostate cancer, lung canCer, thyroid cancer and/or leukemia. (7) The immunity-inducing agent according to any one of (1) to (6), further comprising an immunoenhancer. (8) The immunity-inducing agent according to (7), wherein the immunoenhancer is at least one selected from the group consisting of Freund's incomplete adjuvant; Montanide; poly-I:C and derivatives thereof; CpG oligonucleotides; interleukin-12; interleukin-I8; interferon-o; interferon-p; interferon-co; interferon-1; and Flt3 ligand. EFFECT OF THE INVENTION [00r2] By the present invention, a novel immunity-inducing agent useful for therapy, prophylaxis and/or the tike of cancer is provided. As concretely described in the later-mentioned Examples, adminisfiation of the polypeptide used in the present 15 20 25 10 invention to a living body enables induction of immunocytes in the living body, and a cancer which has already occurred can be reduced or regressed. Therefore, the polypeptide is useful for therapy and/or prophylaxis of cancer. BRIEF DESCRIPTION OF THE DRAWINGS [0013] Fig. I shows the expression patterns of the identified KATNAL1 gene in dog normal tissues, tumor tissues and cancer cell lines. Reference numeral 1, the expression patterns of the dog KATNALI gene in various dog tissues and cell lines; reference numeral 2,the expression patterns of the dog GAPDH gene in various dog tissues and cell lines. Fig.2 shows the expression patterns of the identified KATNAL1 gene in human normal tissues, tumor tissues and cancer cell lines. Reference numeral 3, the expression pattems of the human KATNAL1 gene in various human tissues and cell lines; reference numeral 4, the expression patterns of the human GAPDH gene in various human tissues and cell lines. Fig. 3 shows the expression patterns of the identified KATNAL1 gene in mouse normal tissues, tumor tissues and cancer cell lines. Reference numeral 5, the expression patterns of the mouse KATNALI gene in various mouse tissues and cell lines; reference numeral6, the expression pattems of the mouse GAPDH gene in various mouse tissues and cell lines. BEST MODE FOR CARRYING OUT THE INVENTION [00r4] Examples of the polypeptide contained in the immunity-inducing agent of the present invention as an effective ingredient include the following. ln the present invention, the term "polypeptide" means a molecule formed by a plurality of amino acids linked together by peptide bonds, and includes not only polypeptide molecules having large numbers of amino acids constituting them, but also low-molecular- 15 20 25 10 weight molecules having small numbers of amino acids (oligopeptides), and full- . length proteins. The present invention also includes the full-length KATNALI proteins having the amino acid sequence of SEQ ID NO:2,4, 8, 10 or 12. [001s] (a) A polypeptide that is composed of not less than 7 consecutive amino acids in a polypeptide having the amino acid sequence of sEQ ID No:4, z, g, l0 or r2 in SEQUENCE LISTING, and has an immunity-inducing activity, (b) A polypeptide composed of not less than 7 amino acids, which polypeptide has a sequence identity of not less than 85ohto the pollpeptide (a) and an immunity-inducing activity. (c) A polypeptide that comprises the polypeptide (a) or (b) as a partial sequence thereof, and has an immunity-inducing activity. [0016] In the present invention, the term "having an amino acid sequence" means that amino acid residues are arrayed in such an order. Therefore, for example, "polypeptide having the amino acid sequence of SEQ ID NO:2" means the polypeptide having the amino acid sequence of Met Asn Leu Ala ... (snip) ... Glu Phe Gly Ser AIa shown in SEQ ID NO:2, which polypeptide has a size of 490 amino acid residues. Further, for example, "polypeptide having the amino acid sequence of SEQ ID NO:2" may be referred to as "polypeptide of SEQ ID NO:2" for short. This also applies to the term "having a base sequence". In this case, the term "having" may be replaced with the expression "composed of'. [0017] As used herein, the term "immunity-inducing activity" means an ability to induce immunocytes that secrete cytokines such as interferon in a living body. [0018] Whether or not the polypeptide has an immunity-inducing activity can be 15 20 25 7 10 confirmed using, for example, the known ELISPOT assay. More specifically, for example, as described in the Examples below, cells such as peripheral blood mononuclear cells are obtained from a living body subjected to administration of the polypeptide whose immunity-inducing activity is to be evaluated, and the obtained cells are then cocultured with the polypeptide, followed by measuring the amount(s) of a cytokine(s) produced by the cells using a specific antibody/antibodies, thereby enabling measurement of the number of immunocytes among the cells. By this, evaluation of the immunity-inducing activity is possible. [001e] Alternatively, as described in the later-mentioned Examples, administration of the recombinant polypeptide of any of (a) to (c) described above to a tumor-bearing animal allows regression of the tumor by its immunity-inducing activity. Thus, the above immunity-inducing activity can be evaluated also as an ability to suppress the growth of cancer cells or to cause reduction or disappearance of a cancer tissue (tumor) (hereinafter referred to as "antitumor activity"). The antitumor activity of a polypeptide can be confirmed by, for example, as more specifically described in the Examples below, observation of whether or not a fumor is reduced when the polypeptide was actually administered to a tumor-bearing living body. [0020] Altematively, the antitumor activity of a polypeptide can be evaluated also by observation of whether or not T cells stimulated with the polypeptide (that is, T cells brought into contact with antigen-presenting cells presenting the polypeptide) show a cytotoxic activity against tumor cells invitro. The contact between the T cells and the antigen-presenting cells can be carried out by their coculture in a liquid medium, as mentioned below. Measurement of the cytotoxic activity can be carried out by, for example, the known method called slCr release assay described in Int. J. Cancer, 58: p 317, 1994. In cases where the polypeptide is to be used for therapy and/or 15 20 25 9 10 15 20 prophylaxis of cancer, the evaluation of the immunity-inducing activrty is preferably carried out using the antitumor activity as an index, although the index is not limited thereto. [0021] Each of the amino acid sequences of SEQ ID NOs:2,4, 8, 10 and l2 in SEQUENCE LISTING disclosed in the present invention is an amino acid sequence of I(ATNALI protein that was isolated, by the SEREX method using a dog testisderived cDNA library and serum of a tumor-bearing dog, as a polypeptide that specifically binds to an antibody existing in the serum of a tumor-bearing dog, or a homologous factor of the polypeptide in human, cow, horse or chicken (see Example 1). Human KATNALI, which is the human homologous factor of dog KATNALI, has a sequence identity of 95%o in terms of the base sequence and 98% interms of the amino acid sequence; bovine KATNALI, which is the bovine homologous factor, has a sequence identity of 9l% in terms of the base sequence and 9TYointerms of the amino acid sequence; equine KATNALI, which is the equine homologous factor, has a sequence identity of 87Yo in terms of the base sequence and 88% in terms of the amino acid sequence; and chicken KATNALI, which is the chicken homologous factor, has a sequence identity of 81% in terms of the base sequence and 90Yo in terms of the amino acid sequence. [0022) The polypeptide (a) is a polypeptide composed of not less than 7 consecutive, preferably 8, 9 or not less than l0 consecutive, amino acids in the polypeptide having the amino acid sequence of SEQ ID NO:2, 4, 8, l0 or 12, and has an immunityinducing activity. The polypeptide is more preferably a polypeptide composed of an amino acid sequence having a sequence identity of not less than 85Yoto the amino acid sequence of SEQ ID NO:4, and the polypeptide especially preferably has the amino acid sequence of SEQ ID NO:2,4, 8, 10 ot 12. As is known in the art, a 25 l0 10 polypeptide having not less than about 7 amino acid residues can exert its antigenicity and immunogenicity. Thus, a polypeptide having not less thanT consecutive amino acid residues in the amino acid sequence of SEQ ID NO:2 or 4 can have an immunity-inducing activity, so that the polypeptide can be used for preparation of the immunity-inducing agent of the present invention. [0023] As a principle of immune induction by administration of a cancer antigenic polypeptide, the following process is known: a polypeptide is incorporated into an antigen-presenting cell and then degraded into smaller fragments by peptidases in the cell, followed by being presented on the surface of the cell. The fragments are then recognized by a cytotoxic T cell or the like that selectively kills cells presenting the antigen. The size of the polypeptide presented on the surface of the antigenpresenting cell is relatively small and about 7 to 30 amino acids. Therefore, from the viewpoint of presenting the polypeptide on the surface of the antigen-presenting cell, one preferred mode of the above-described polypeptide (a) is a polypeptide composed of about 7 to 30 consecutive amino acids in the amino acid sequence of sEQ ID NO:2,4, 8, l0 or 12, and more preferably, a polypeptide composed of about 8 to 30 or about 9 to 30 amino acids is suffrcient as the polypeptide (a). In some cases, these relatively small polypeptides are presented directly on the surface of antigen-presenting cells without being incorporated into the antigen-presenting cells. [0024] Further, a polypeptide incorporated into an antigen-presenting cell is cleaved at random sites by peptidases in the cell to yield various polypeptide fragments, which are then presented on the surface of the antigen-presenting cell. Therefore, administration of a large polypeptide such as the full-length region of SEQ ID NO:2, 4, 8, 10 or 12 inevitably causes production of polypeptide fragments by degradation in the antigen-presenting cell, which fragments are effective for immune induction 15 20 25 il 10 15 20 via the antigen-presenting cell. Therefore, also for immune induction via antigenpresenting cells, a large polypeptide can be preferably used, and the polypeptide may be composed of not less than 30, preferably not less than 100, more preferably not less than 200, still more preferably not less than 250 amino acids. The polypeptide may be still more preferably composed of the full-length region of SEe ID No:2, 4, 8, l0 or 12. [002s] The polypeptide (b) is the same polypeptide as the polypeptide (a) except that a small number of (preferably, one or several) amino acid residues are substituted, deleted and/or inserted, which has a sequence identity of not less than 90%, preferably not less than9l%o,more preferably not less than 98%, still more preferably not less than99% or not less than 99.5% to the original sequence and has an immunity-inducing activity. It is well known in the art that, in general, there are cases where a protein antigen retains almost the same antigenicity as the original protein even if the amino acid sequence of the protein is modified such that a small number of amino acid residues are substituted, deleted and/or inserted. Therefore, since the polypeptide (b) may also exert an immunity-inducing activity, it can be used for preparation of the immunity-inducing agent of the present invention. Further, the polypeptide (b) is also preferably a polypeptide having the same amino acid sequence as the amino acid sequence of SEQ ID No:2, 4, 8, 10 or 12 except that one or several amino acid residues are substituted, deleted and/or inserted. As used herein, the term "several" means an integer of 2 to 10, preferably an integer of 2 to 6, more preferably an integer of 2to 4. [0026] As used herein, the term "sequence identity" of amino acid sequences or base sequences means the value calculated by aligning two amino acid sequences (or base sequences) to be compared such that the number of matched amino acid residues (or 25 t2 10 bases) is ma: