Autoantigen and proteins structurally related thereto for use in immunotherapy of autoimmune diseases

Abstract

The invention relates to T-cell tolerance-inducing proteins, more specifically to one or more proteins containing an amino acid sequence at least 70% homologous to HC gp-39, specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a.) for use as therapeutic agents. The invention relates to the use of proteins in the treatment of chronic destruction of articular cartilage in autoimmune diseases, to pharmaceutical compositions containing autoantigens and / or proteins according to the invention, to diagnostic methods suitable for detecting autoreactive T cells in test samples, and to reagent kits usable in the method. The solution according to the invention is suitable for inducing specific T-cell tolerance in patients suffering from T-cell-mediated cartilage damage, and for creating animal test models of arthritis, and for detecting autoreactive T cells. à

Description

The invention relates to novel autoantigens and related proteins, and their use in the treatment of chronic destruction of articular cartilage in autoimmune diseases, pharmaceutical compositions containing the autoantigens and / or proteins of the invention, diagnostic methods suitable for detecting autoreactive T cells in test samples, and reagent kits for use in the method. The solution according to the invention can be advantageously used for inducing specific T-cell tolerance in patients suffering from T-cell-mediated cartilage damage, for creating animal test models of arthritis, and for detecting autoreactive T cells. The principle basis of the functioning of the immune system is the ability to distinguish between foreign antigens (non-self antigens) and autoantigens (self antigens that originate from the individual's own body), which is achieved through internal tolerance to autoantigens. The immune system protects the individual from foreign antigens and responds to foreign antigens by activating specific cells, such as T and B lymphocytes, and by producing solution-phase factors, such as interleukins, antibodies, and complement components. The antigen that triggers the immune response is digested by antigen-presenting cells (APCs), which express the antigen on the cell surface in association with the major histocompatibility complex (MHC) II glycoprotein. The MHC-glycoprotein - antigen fragment - complex is presented to the T cell, which recognizes the antigen bound to MHC II by its T cell receptor. The T cell is activated, i.e., proliferates and / or produces interleukins, thereby triggering the proliferation of activated lymphocytes directed against the challenged antigen [Grey et al., Sci. Am., 261: 38-46 (1989)]. Self-antigens are also continuously degraded and presented as antigenic fragments by MHC glycoproteins to T cells [Jardetsky et al., Nature 353, 326-329 (1991)]. The ability to recognize self is therefore a fundamental property of the immune system. Under normal circumstances, the immune system is tolerant to self-antigens, and self-antigens do not elicit an immune response. When tolerance to self-antigens is lost, one or more self-antigens trigger an immune response, causing the activation of autoreactive T cells and the production of autoantibodies. This phenomenon is called autoimmunity. Since the immune response is usually destructive, that is, it destroys the invading foreign antigen, autoimmune processes can lead to the destruction of the body's own tissues. The involvement of T cells in autoimmune diseases has been demonstrated in several studies. In mice, experimental autoimmune encephalomyelitis (EAE) is caused by a narrow subset of T cells that are specific for a single epitope of myelin basic protein (MBP) complexed with MHC II. In Lewis rats, which are susceptible to various autoimmune diseases, the disease has been shown to be mediated by T cells. It is assumed that human autoimmune diseases are also associated with the generation of autoaggressive T cells. A destructive autoimmune process plays a role in various diseases, such as rheumatoid arthritis (RA), in which articular cartilage is damaged by a chronic inflammatory process, due to the presence of large numbers of activated lymphocytes and MHC class II-expressing cells. The mere presence of cartilage seems to be necessary to maintain the local inflammatory response: cartilage degradation in RA has been shown to be associated with the activity of cartilage-specific autoreactive T cells [Sigall et al., Clin. Exp. Rheumat. 6:59 (1988); Glant et al., Biochem. Soc. Trans. 18:796 (1990); Burmester et al., Rheumatoid arthritis, eds. Smolen, Kaidén and Maini, Springer-Verlag Berlin Heidelberg, (1992). Furthermore, it has been shown that surgical removal of cartilage reduces the degree of inflammation [G. S. Panayi et al., Clin. Exp. Rheumatol. 11. (supplementary volume 8): S1-S8 (1993)].Therefore, it is assumed that cartilage proteins are autoantigens (targets of autoantibodies) that can stimulate T cells. Activation of these autoreactive T cells leads to the development of autoimmune disease. However, the identification of the autoantigenic component involved in the development of rheumatoid arthritis remains a difficult question to answer. The inflammatory reaction leading to cartilage destruction can be treated with a variety of drugs, including steroid drugs. However, these are often non-specific immunosuppressive agents that have toxic side effects. Due to the disadvantages of non-specific immunosuppression, it is a less commonly used therapy. Antigen-specific, non-toxic immunosuppression is an attractive alternative to non-specific immunosuppression. In antigen-specific therapy, the patient is treated with antigens with a sequence homologous to the targeted antigen or its amino acid sequence, or with synthetic T-cell-reactive peptides derived from the above-mentioned autoantigen or antigen. These synthetic peptides correspond to the T-cell epitope of the antigen; they can be used to induce systemic immune tolerance, i.e., specific T-cell tolerance, to themselves or to the antigen. Although it seems counterintuitive to desensitize the immune system to the same antigen that is responsible for its activation, controlled administration of the targeted antigen can be a very effective way to desensitize the immune system.Desensitization of the immune system, or induction of immunological tolerance, is based on the long-observed phenomenon that animals that have previously been fed or inhaled an antigen or epitope are less able to mount a systemic immune response to said antigen or epitope when it enters their bloodstream. In order to successfully apply tolerance therapy in the treatment of T-cell-mediated cartilage damage, it is necessary to identify the HU 221 348 Β1 autoantigen or antigens whose amino acid sequence is homologous to the amino acid sequence of the targeted antigen, in order to desensitize patients to those autoantigens that activate T cells responsible for the inflammatory process. In developing the solution according to the invention, our goal was to create an autoantigen and proteins whose amino acid sequence shows a sufficient degree of homology to the autoantigen, and which autoantigen and / or protein is suitable for inducing specific T-cell tolerance in patients suffering from T-cell-mediated cartilage damage. In developing the solution according to the invention, our goal was also to create animal test models of arthritis that can be used in the screening of new drugs for alleviating the symptoms of arthritis. In addition, our goal was to develop a method suitable for detecting autoreactive T cells involved in the damage of articular cartilage and a reagent kit usable in the method. The discovery that human cartilage glycoprotein 39 (HC gp-39) is a targeted autoantigen in RA patients, which activates specific T cells and thereby causes or mediates an inflammatory process, was unexpected. The arthritogenic nature of HC gp-39 was also confirmed by experiments with “Balb-c” transgenic mice. Balb-c mice showed signs of arthritis after a single subcutaneous injection of the peptide. The course of the disease induced by HC gp-39 was characterized by periodic relapses in the fore and / or hind limbs, and the mild arthritis gradually became more severe. A symmetrical distribution of the affected joints was also observed, which, together with the periodic relapses and nodule formation, is reminiscent of the course of arthritis, especially RA. Even more surprisingly, we found that treatment with HC gp-39 resulted in immunological tolerance and, more importantly, delayed and / or prevented the development of arthritis. It was also unexpected to find that proteins which have an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39 are capable of inducing arthritis when injected into animals. More specifically, proteins which contain an amino acid sequence at least 50% homologous to the sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTH IIYSFANISND [SEQ ID NO: 1 (hereinafter referred to as SEQ ID NO: 1)] were capable of inducing arthritis in animals in the same manner as HC gp-39. These arthritogenic proteins comprise an amino acid sequence which is preferably at least 70%, more preferably 80%, most preferably 90% homologous to the amino acid sequence of HC gp-39, in particular to the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1a). The percent sequence homology between the arthritogenic proteins of the invention and SEQ ID NO: 1 is understood to mean the homology that can be determined using commonly used sequence comparison programs such as FASTA [W. R, Pearson and DJ Lipman, Proc. Natl. Acad. Sci. USA, 85, 2444-2448, (1988)]. Suitable arthritogenic proteins according to the invention include, for example, porcine 38 kDa heparin-binding protein, bovine 39 kDa whey protein, human YKL-39 protein, mouse breast-regressing 39 kDa protein (brp39), human fallopian tube-specific glycoprotein, mouse fallopian tube-specific glycoprotein, hamster fallopian tube-specific glycoprotein, bovine fallopian tube-specific glycoprotein, human chitotriosidase precursor protein and mouse YM-1 secretory protein precursor. The arthritogenic proteins according to the invention are highly suitable for inducing systemic tolerance of the immune system to autoantibodies homologous to these proteins and can be used to delay or prevent the development of arthritis in mammals. HC gp-39 is present in the serum of both diseased and healthy adults, but the serum concentration in patients is approximately double that of healthy adults. In addition, mRNA encoding HC gp-39 is found in the synovium or cartilage of RA patients, whereas surgically removed cartilage samples from healthy adults do not contain significant amounts of mRNA encoding HC gp-39. When articular chondrocytes and synovial cells are cultured, HC gp-39 becomes the major secretory product in their culture [Hakala et al. J. Biol. Chem., 268, No.34, 25803 (1993)]. Hakala et al. do not address or suggest the arthritogenic nature of HC gp-39 in their article, nor is such a reference made in other publications. Proteins with at least 50% homology to the amino acid sequence of HC gp-39, specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (1. a.), have been previously described and described. Although the identification of the porcine heparin-binding protein is reported by Shackleton et al. [J. Biol. Chem., 270, No.270. 13076-13083 (1995)], the function of the protein has not been identified. The isolation and characterization of the bovine 39 kDa whey protein was reported by JJ Rejman et al. [Biochem. Biophys. Res. Comm. 150, No. 1, 329-334, (1988)]. The mouse breast regressing 39 kDa protein (brp39) was described by Morrison and Leder [Oncogene 9, 3417, (1994)]. The cloning and amino acid sequence of the human fallopian tube-specific glycoprotein cDNA were described by Arias et al. [Biology of Reproduction 57, 685-694, (1994)].Other mammalian oviduct-specific glycoproteins, such as mouse and hamster oviduct-specific glycoproteins, are disclosed in Japanese Patent Application Publication No. JP-A-07107979 (Kinosei Peptide Kenkyusho KK). The purification and cloning of bovine oviduct-specific glycoprotein is described by Y Sendai et al. [Biol. of Reprod. 50, 927-934 (1994)]. The human chitotriosidase precursor protein is secreted by activated human macrophages and is acti3. HU 221 348 Bl. The cloning and amino acid sequence of the chitotriosidase cDNA were described by Boot et al. [J. Biol. Chem. 270, No. 44, 26252-26256)]. The amino acid sequence of the murine YM-1 secretory protein precursor was deposited by Chan et al. in the EMBL Databank in June 1992 under accession number M94584, unpublished data. The amino acid sequence of the human chondrocyte YK.L-39 protein was described by Hu et al. [J. Biol. Chem. 271, No. 32, 19415-19420 (1996)]. However, none of the above publications address or refer to the arthritogenic nature of the proteins of the invention, nor to the fact that these proteins can be used as therapeutic agents in therapy for inducing specific T-cell tolerance to HC gp-39 in mammals, particularly humans, suffering from T-cell-mediated cartilage damage, such as arthritis, particularly rheumatoid arthritis. Thus, according to the invention, HC gp-39 and proteins containing an amino acid sequence that is at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREG DGSCFPDALD-RFLCTHIIYSFANISND (No. 1 a.), are highly suitable for use in therapy aimed at inducing specific T-cell tolerance to HC gp-39 in patients suffering from T-cell-mediated cartilage damage, such as arthritis, in particular rheumatoid arthritis. Also within the scope of the invention are fragments of HC gp-39 and arthritogenic proteins according to the invention, which are suitable for inducing specific T-cell tolerance to the HC gp-39 autoantigen in the affected cartilage. WO 95 / 01995 and WO 95 / 02188 describe the use of HC gp-39 as a diagnostic marker for RA, but do not disclose or suggest the arthritogenic nature of HC gp-39. Nowhere is the use of HC gp-39 or fragments thereof or the T-cell reactive proteins of the invention mentioned or suggested for inducing T-cell specific tolerance to the HC gp-39 autoantigen in the affected cartilage. HC gp-39, as well as arthritogenic proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), and fragments of arthritogenic proteins according to the invention can also be produced by recombinant DNA methods. HC gp-39, as well as arthritogenic proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), or the nucleic acid sequence encoding the arthritogenic proteins according to the invention or their multimers can be inserted into an expression vector. Suitable expression vectors include plasmids, cosmids, viruses and "YACs" f'Yeast Artificial Chromosome", i.e. artificial yeast chromosome), which contain the control regions necessary for replication and expression. The expression vector can be expressed in a host cell. Suitable host cells for this purpose are, for example, bacteria, yeast or mammalian cells. These methods are well known in the art (Sambrooke et al. Molecular Cloning: a Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, 1989.) Bovine whey protein (the sequence of which is provided here) can be produced in a host cell using recombinant DNA methods. Thus, the invention also provides a cDNA encoding bovine whey protein (SEQ ID NO: 3) and the bovine whey protein, the sequence of which is given in SEQ ID NO: 2. It is understood that fragments can also be prepared in accordance with the teachings of the invention. The term "fragment" may refer to any amino acid sequence that is part of the amino acid sequence of a protein of common origin, structure and mechanism of action with the proteins within the scope of the present invention. The appropriate fragments of the arthritogenic proteins of the invention can be prepared by one of the known organic chemical methods of peptide synthesis. Organic chemical methods of peptide synthesis involve the coupling of the desired amino acids by condensation reactions, either in a homogeneous phase or even in a so-called solid phase. The most common methods of the above condensation reactions are the carbodiimide, azide, mixed anhydride and activated ester methods [The Peptides, Analysis, Synthesis, Biology 1-3. Ed. Gross, E. and Meienhofer, J. (1979, 1980, 1981) Academic Press, Inc.]. A description of the "solid phase" preparation of the above-described HC gp-39 and suitable fragments of the arthritogenic proteins of the invention according to the invention can be found, for example, in J. Amer. Chem. Soc. 85, 2149 (1963) and Int. J. Peptide Protein Res. 35: 161-214 (1990). A preferred solid phase is, for example, p-alkoxybenzyl alcohol resin, as described by Wang (J. Am. Chem. Soc. 95:1328 (1974)). After synthesis, the peptides can be cleaved from the solid phase under mild conditions. After synthesis, the desired amino acid sequence is cleaved from the resin (support) with, for example, trifluoroacetic acid containing radical scavengers, such as triisopropylsilane, anisole or ethanediol, or possibly thioanisole. The reactive group, which cannot participate in the condensation reaction, as mentioned, can be effectively protected with groups which can be subsequently removed by hydrolysis with acid or base or by reduction. A more detailed discussion of possible protecting groups can be found in The Peptides, Analysis, Synthesis, Biology, vols. 1-9 (Eds. Gross, Udenfriend and Meienhofer; Academic Press, 1979-1987). The protecting groups can be cleaved by a number of conventional methods, depending on the nature of the individual groups, for example, with trifluoroacetic acid or by mild reduction cata4 HU 221 348 BI by hydrogenation on a catalyst, such as palladium, or with HBr in glacial acetic acid. Although it may seem paradoxical to desensitize the immune system with the same antigen that is responsible for activating the immune system, this desensitization is based on the long-standing observation that animals fed or inhaled with an antigen or epitope were less able to mount a systemic immune response to said antigen or epitope when it enters the circulation. Thus, the controlled administration of proteins containing an amino acid sequence at least 50% homologous to HC gp-39 and / or the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), may be effective in desensitizing the immune system. Fragments of the proteins of the invention that are capable of desensitizing patients to HC gp-39 are also within the scope of the invention. In the present invention, patients suffering from autoreactive T cell chondromalacia can be treated with a pharmaceutical composition comprising HC gp-39, one or more proteins having at least 50% homology to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a), or one or more fragments of the proteins of the invention, and a pharmaceutically acceptable carrier; the treatment aims to induce tolerance of the patients' specific T cells to HC gp-39 and to reduce the degree of the inflammatory reaction. Proteins that can be used in the pharmaceutical composition of the invention contain an amino acid sequence that is at least 70%, preferably 80%, more preferably 90% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDAL DRFLCTHIIYSFANISND (No. 1 a). Proteins that can be used in the pharmaceutical composition of the invention include, for example, porcine heparin-binding 38 kDa protein, bovine 39 kDa whey protein, mouse breast regressing (brp 39) protein, mouse fallopian tube-specific glycoprotein, hamster fallopian tube-specific glycoprotein, bovine fallopian tube-specific glycoprotein, human YKL-39, human fallopian tube-specific glycoprotein, human chitotriosidase precursor protein and mouse YM-1 secretory precursor protein. DNA (expression) vectors that contain HC gp-39, or a protein that is at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDAL DRFLCTHIIYSFANISND (No. 1 a.), or DNA encoding fragments of the proteins of the invention, may also be advantageously used in the pharmaceutical composition of the invention. By targeting the DNA expression vector, a protein containing an amino acid sequence at least 50% homologous to the amino acid sequence of recombinant HC gp-39, or to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGD GSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), or fragments of the proteins according to the invention can reach a level that is achievable upon direct administration of a pharmaceutical composition containing HC gp-39 or the peptides. The advantage of the HC gp-39 autoantigen, or of arthritogenic proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, more specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCF PDALDRFLCTHIIYSFANISND (No. 1 a.), or of fragments of the proteins according to the invention is that their specific "tolerizing" effect is exerted only against autoreactive Τ' cells, thus leaving other components of the immune system unaffected, in contrast to the non-specific immunosuppressive effects of non-specific immunosuppressive drugs. Treatment with arthritogenic proteins containing an amino acid sequence at least 50% homologous to the autoantigen or the amino acid sequence of HC gp-39, more specifically the amino acid sequence YKLVCYYTSWSQYREGD GSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), or with fragments of the proteins according to the invention, is safe and has no toxic side effects. Tolerance can be achieved with high or low doses of the autoantigen of the invention or the proteins of the invention. The dose will generally be 0.01-1000 pq peptide per kilogram of body weight, more preferably 0.5-500 pg, even more preferably 0.1-100 pg. Pharmacological carriers may be those commonly used in medicine, such as sterile saline, lactose, sucrose, calcium phosphate, gelatin, dextrin, agar, pectin, peanut oil, olive oil, sesame oil, or water. The carrier may be, for example, a class II MHC molecule, optionally encapsulated in liposomes. The pharmaceutical composition of the invention may further comprise one or more adjuvants. Suitable adjuvants include aluminum hydroxide, aluminum phosphate, amphigen, tocophenols, monophosphenyl lipid A, muramyl dipeptide and saponins such as Quill A. The amount of adjuvant is determined by the nature of the adjuvant. The pharmaceutical composition of the invention may additionally comprise one or more stabilizers, such as carbohydrates, including sorbitol, mannitol, starch, sucrose-dextrin and glucose; or proteins, such as albumin, casein; and buffers, such as alkaline phosphates. Suitable routes of administration include intramuscular injection, subcutaneous injection, intravenous injection, intraperitoneal injection, oral and intranasal administration. Oral and intranasal administration are preferred. Due to its arthritic nature, HC gp-39 is at least 50% homologous to the amino acid sequence of HC gp-39, specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (number 1 a). HU 221 348 B1 acid sequence containing proteins can be used to induce clinical arthritis in animals. Administration of a small amount of HC gp-39, or one or more proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGD GSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), or one or more fragments derived from the proteins of the invention, results in the development of arthritis-like symptoms in animals. In Balb / c transgenic mice, a single subcutaneous injection of the HC gp-39 protein, or one or more proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (1. a.), showed signs of arthritis. The disease induced by HC gp-39, as well as by the amino acid sequence of HC gp-39, specifically the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHII YSFANISND (1. a.)The course of the disease induced by a protein containing at least 50% homology to the amino acid sequence of the protein (numbered 1) is characterized by periodic relapses in the fore and / or hind legs, and a mild arthritis that gradually becomes more severe. A symmetrical distribution of the affected joints has also been observed, which, together with the periodic relapses and nodule formation, is reminiscent of the course of arthritis, especially RA. The animals concerned thus provide a suitable animal model for studying the mechanism of initiation and progression of arthritis. In addition, said animals can be used to search for active ingredients suitable for the treatment of arthritis and to study the effect of drugs on the course of arthritis. Preferably, mice can be used as animal models of arthritis, in particular rheumatoid arthritis. In order to induce arthritis in said animals, an appropriate amount of HC gp-39 or the protein of the invention should be administered. An appropriate amount is 0.1-1000 pg, preferably 1-100 pg, more preferably 10-50 pg per kilogram of body weight. The amount of HC gp-39, or a protein with at least 50% homology to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFP DALDRFLCTHIIYSFANISND (No. 1 a.), or fragments thereof, depends on the route of administration, the duration of administration and the species of animal. The appropriate route of administration is as described. For the induction of arthritis, proteins or peptides of the invention containing at least 50% homologous amino acid sequence with HC gp-39, or with the amino acid sequence of HC gp-39, in particular with the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHII YSFANISND (No. 1 a.) may contain one or more of the stabilizers and adjuvants already described. HC gp-39, proteins containing an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (No. 1 a.), or fragments thereof according to the invention, are highly suitable for use in a diagnostic method, for detecting activated autoreactive T cells involved in chronic inflammation of articular cartilage. The diagnostic method according to the invention consists of the following steps: a) isolating peripheral blood mononuclear cells (PBMC) from the individual's blood sample; b) culturing said PBMC cells under suitable conditions; c) incubating said PBMC culture with an autoantigen, protein or fragments thereof according to the invention; and d) detecting a T-cell response, such as a proliferative reaction, indicative of the presence of activated autoreactive T cells in the individual. In the case where the proliferative response of autoreactive T cells is measured as a response, the proliferation can be monitored by incorporation of radioisotopes, such as 3H-thymidine. The response of autoreactive T cells in the presence of PBMCs can also be measured by measuring cytokine release, using cytokine-specific ELISA, or by determining cytotoxicity, using 5•chromium release. Another detection method is the measurement of activation markers, such as IL-2R, using FACS analysis. Thus, the invention provides a diagnostic composition comprising one or more peptides according to the invention and a suitable detection reagent. Depending on the method of detection, the detection reagent may be a radioisotope, an enzyme, or antibodies specific for the cell surface or activation markers. The invention also provides detection kits comprising one or more peptides of the invention. These kits are suitable for use in the diagnostic method of the invention. Thus, the method of the invention is suitable for determining whether HC gp-39-reactive autoaggressive T cells are present in patients suffering from T-cell-mediated cartilage damage, such as arthritis, in particular rheumatoid arthritis. If HC gp-39-specific T cells are present, then by inducing tolerance of these T cells, a pharmaceutical composition comprising HC gp-39, or arthritogenic proteins having an amino acid sequence at least 50% homologous to the amino acid sequence of HC gp-39, in particular the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHII YSFANISND (Ia), or peptides of the invention or combinations thereof, may delay or prevent the development of arthritis. Below, the solution according to the invention is illustrated by examples, which, however, do not narrow its scope of protection. Here we provide a brief description of the figures. Figure 1.: Initiation and progression of arthritis in Balb / c mice treated and untreated with HC gp-39. HU 221 348 Bl AS = “arthritic score”, “hit”; total arthritis-related events in treated animals after treatment. N = number of affected animals after sensitization. Figure 2: Initiation and progression of arthritis in Balb / c mice after administration of 0.2 pg, 1 pg, 5 pg, and 25 pg of bovine serum albumin. Post-treatment initiation and progression are characterized by cumulative hits / day (total hits in affected animals). Example 1 Methods Purification of HC gp-39 from osteosarcoma cell line MG63 MG63 (ATCC CRL 1427 human osteosarcoma) 15 cells were cultured in DMEM / HAM F12 serum-free medium in cell culture apparatus. HC gp-39 was purified from the cell supernatant by heparin affinity chromatography followed by super dex 75 chromatography. Purity was checked by SDS-PAGE. N-20 terminal amino acid sequencing confirmed that the protein was identical to the protein described by Hakala et al. Arthritogenic nature of HC gp-39 in Balb / c mice 2x4 female Balb / c mice (Harlan CPB, Zeist, The Netherlands) were injected into the chest with 10 or 50 pg of purified HC 25 gp-39 [in PBS (0.5 M NaCl, 0.01 M sodium phosphate buffer, pH 7.5)] and incomplete Freund's adjuvant (IFA) A 1:1 mixture was injected subcutaneously, while 4 control animals were inoculated with PBS (mixed with IFA in a 1:1 ratio). The appearance of clinical arthritis symptoms was monitored daily. When assessing the severity of arthritis, each limb was scored between 0 and 3 (based on the report of Glant et al.). Briefly: 0 points: no change, 1 point: erythema (redness of the skin) and swelling, 2 points: swelling and deformity, 3 points: inability to move due to loss of extension and flexion ability. Tolerance induction by intranasal administration of HC gp-39 28 pg of protein (2 x 10 µl) was administered intranasally to 10 female Balb / c mice (lightly anesthetized with Enflurance) using a PT45 microtubule and Hamilton syringe. The antigen was administered on days 15, 10, and 5 before arthritis induction. Control animals were treated in the same manner but received only the buffer (PBS) (Table 1). Immunological tolerance was determined by measuring the delayed type hypersensitivity (DTH) reaction after the above-described sensitization on day 0 using 10 pg of protein. After sensitization on day 0, on day 8, 10 pg of HC gp-39 was injected in a volume of 50 µl into the left hind paw (challenge). The DTH response was given by the increase in paw size: ([left swelling (mm x 10'3)-right swelling (mm x 10_3)] / right swelling (mm x 103)) x 100%. Paw swelling was determined using a homemade micrometer at 0, 24 and 48 hours after challenge. The tolerance to arthritis induction was further investigated in mice up to day 31 after sensitization; the appearance of clinical signs was monitored daily. The severity of arthritis was assessed as previously described. Table 1 The schema of the privilege of tolerance Day Tolerance induction with HC gp Untreated -15 28 pg HC gp-39 intranasally PBS -10 28 pg HC gp-39 intranasally PBS -5 28 pg HC gp-39 intranasally PBS 0 10 pg HC gp-39 subcutaneously 10 pg HC gp-39 subcutaneously 8 10 pg HC gp-39 in the sole 10 pg HC gp-39 in the sole 9 24-hour DTH 24-hour DTH 10 48-hour DTH 48-hour DTH 0-31 Arthritis symptoms Arthritis symptoms number (hits) number (hits) DTH: delayed-type hypersensitivity. PBS: 0.5 M NaCl, 0.01 M sodium phosphate buffer, pH 7.5 Results Arthritogenicity of HC gp-39 After injection of 50 pg of He gp-39 mixed with IFA, all mice showed signs of progressively severe arthritis (Table 2). Arthritic symptoms were first observed in the forelimbs of three out of four mice, 15-20 days after sensitization. In the mouse that did not show symptoms in the forelimbs, arthritis developed in the hindlimbs 34 days after sensitization. The course of the disease induced by HC gp-39 is characterized by periodic relapses in the forelimbs and / or hindlimbs, and the mild arthritis 55 gradually becomes more severe (the course of the disease was monitored for 62 days). Very often (>50%) we observed a symmetrical distribution of affected joints, meaning that symptoms appeared on both legs at the same time in both forelimbs and hindlimbs. HU 221 348 Bl Arthritis induction was performed similarly, using 10 pg HC gp-39 instead of 50 pg mixed with IFA. The number of “hits” characteristic of arthritis was slightly lower (data not shown). Three of the four mice developed severe arthritis. One mouse showed only mild symptoms during the experiment. Control mice showed no signs of arthritis during the entire experiment. In conclusion, both 10 and 50 pg of protein were sufficient to induce progressive arthritis in Balb / c mice. The chronic nature of arthritis induction with HC gp-39, characterized by periodic relapses and a symmetrical distribution of affected joints, is reminiscent of the course of rheumatoid arthritis (RA). Table 2 Initiation and progression of arthritis in Balb / c mice sensitized with HC gp-39 Sensitization (n=4) Onset of arthritis (day) Arthritis symptoms MV Hv none mild severe PBS cont. - - 4 0 0 10 pg HC gp-39 -,13,15, 57 32, 34, 36, 43 0 1 3 50 pg HC gp-39 13, 15, 15,48 29, 34, 34, 53 0 0 4 MV: forelimb. HV: hindlimb. Cont.: controls. Arthritis symptoms: none: score=0; mild: score less than 2 per animal; severe: score >3 per animal. The degree of immunological tolerance determined by DTH testing 25 Control mice vaccinated with HC gp-39 on day 0 mounted a strong antigen-specific DTH response, suggesting that sensitization with HC gp-39 had elicited a cellular immune response. 30 In contrast, intranasal administration of HC gp-39 completely blocked the DTH response to antigen, indicating that HC gp-39-specific T cells had indeed become tolerant. Notably, 4 out of 10 non-tolerized animals developed arthritis in the ankle adjacent to the challenge site. In contrast, the tolerance-induced (“tolerized”) group did not develop arthritis in joints adjacent to the challenge site, suggesting that immunological tolerance to HC gp-39 provides protection against the development of arthritis. Table 3 DTH responses to HC gp-39 following tolerance induction by nasal treatment Treatment Mean % Swelling Arthritis at Ankle 0 hours 24 hours 48 hours Control (n= 10) -1.3 31.4 38.6 4 / 10 Tolerated (n=9) -0.05 3.7 1.5 0 / 9 Tolerance to arthritis induction or progression Balb / c mice that were tolerance-induced with HC gp-39 and untreated were further examined for arthritis initiation and progression. The disease was induced in all members of the (non-tolerized) control group by sensitization with HC gp-39 (Table 4). Seven mice developed severe arthritis, but three only showed mild symptoms (maximum score 2). In contrast, five individuals from the HC gp-39 tolerized group were protected against the disease for the duration of the experiment. In addition, two individuals from the tolerized group showed only mild symptoms for a short period. Three animals developed severe arthritis, characterized by a score of 4. Interestingly, in tolerized animals, arthritis appeared in the hind and forelimbs with a delay of at least 7 and 9 days, respectively (Figure 1). Although fewer animals in the tolerized group became ill, the number of “arthritis hits” per animal in the forelimbs was comparable to that of non-tolerized animals. However, the number of hits per animal on the hind limbs was slightly lower in tolerized animals (Figure 1). HU 221 348 B1 Table 4 Initiation and progression of arthritis in HC gp-39 tolerized and non-tolerized Balb / c mice Animals Onset of arthritis (day) Arthritis symptoms none mild severe control (n= 10) 13-16 0 3 7 tolerized (n=10) 23-24 5 2 3 Onset of arthritis: the appearance of the first symptom - the day most animals become ill. Arthritis symptoms: none: score=0; mild: score less than 2 per animal; severe: score >4 per animal. The above experiments confirm the arthritogenic nature of HC gp-39 in Balb / c mice. The course of the disease induced by HC gp-39 was characterized by periodic relapses in the forelimbs and / or hindlimbs, and the mild arthritis gradually became more severe. We also observed a symmetrical distribution of the affected joints, which, together with the periodic relapses and nodule formation, resembled the course of rheumatoid arthritis. The severe arthritogenic nature of HC gp-39 was demonstrated by a single subcutaneous injection of 10 or 50 pg of the protein; this caused the appearance of arthritis in all animals. The fact that HC gp-39-specific T cells were indeed activated during HC gp-39-sensitization was demonstrated by the induction of HC gp-39-specific DTH responses. These results were further confirmed by the demonstration of an in vitro induced proliferative response in animals immunized with HC gp-39 on their soles (data not shown).It should be noted that non-tolerized animals developed arthritis in the ankle following injection, which indeed suggests a role for HC gp-39-specific T cells in arthritis induction. Intranasal administration of the peptide was used to induce antigen-specific immune tolerance. The results of the experiments showed that intranasal administration of HC gp-39 caused the absence of an immunological response. In mice tolerized with HC gp-39, the DTH reaction following sensitization was completely absent, while in control mice, antigen-specific swelling was observed. These observations suggest that treatment with HC gp-39 leads to peripheral immune tolerance. Of the ten animals in which tolerance was not induced, four developed a DTH reaction in the ankle (inoculated leg) following sensitization, accompanied by arthritis. In contrast, the joints of animals tolerized with HC gp-39 were indeed completely protected, suggesting that autoreactive T cells were effectively silenced. Our view that tolerance induction (“tolerization”) with HC gp-39 provided protection against the disease was further strengthened by the observation that five out of ten animals in the tolerized group remained completely protected throughout the duration of the experiment.Although the other five individuals in the group eventually developed clinical symptoms, arthritis appeared much later, thus we can conclude that HC gp-39-specific T cells play a role in the arthritogenic process and, more importantly, inducing tolerance of these T cells with the pharmaceutical composition of the invention can delay or prevent the development of arthritis. Example 2 Methods Arthritogenic nature of bovine 39 kDa whey protein In Balb / c mice Four times 10 female Balb / c mice (Charles River, Sulzfeld, Germany) were injected subcutaneously with 0.2, 1.5 or 25 pg of a 1:1 mixture of 0.2, 1.5 or 25 pg of bovine 39 kDa whey protein and incomplete Freund's adjuvant (IFA) in a volume of 100 µl (0.5 M NaCl, 0.01 M sodium phosphate buffer, pH 7.5) into the thoracic region, while 10 control animals were injected with PBS (mixed with IFA in a ratio of 1:1). The appearance of clinical arthritis symptoms was monitored daily. When assessing the severity of arthritis, each limb was scored between 0 and 3 (based on the publication of Glant et al.). In short: 0 points: no change, 1 point: erythema (redness) and swelling, 2 points: swelling and deformity, 3 points: inability to move due to loss of extension and flexion ability. Cloning of the bovine 39 kDa whey protein cDNA A bovine mammary Lambda Bluemid(-) cDNA library was amplified (using oligo-dT and random primers prepared by Clontech Laboratories Inc.) using the XL1 Blue MRF cell line as the host cell; library plates and replica filters were prepared according to the manufacturer's recommendations. The filters were hybridized to PvuII fragments of the HC gp-39 cDNA; the cDNA was previously labeled with 32P using an oligo labeling kit (Pharmacia). Positive plaques were amplified and rescreened, and the corresponding phage DNA insert was sequenced using the Thermosequenase kit (Amersham). The sequence is described in SEQ ID NO: 3. At nucleotide position 954, one clone contained Ct, the other Tt. Results Arthritogenic nature of bovine 39 kDa whey protein After injection of a mixture of bovine 39 kDa whey protein and IFA, arthritis gradually developed in all mice (Table 5). The first signs of arthritis were observed on days 8-20 after sensitization. HU 221 348 Bl on the forelimbs and hindlimbs. The course of arthritis induced by bovine whey protein 39 kDa in the forelimbs and / or hindlimbs was characterized by periodic relapses, and the mild arthritis gradually became more severe (the progression of the disease was monitored for 70 days). Very often we also observed a symmetrical distribution of the affected joints, i.e., arthritis symptoms on both sides of the forelimbs or hindlimbs appeared simultaneously. Induction of arthritis was performed similarly to above using 5, 1 or 10 pg of a mixture of 0.2 pg of bovine 39 kDa protein and IFA instead of 25 pg. Mice induced with 1 or even 0.2 pg of bovine 39 kDa protein developed a milder form of arthritis: 7 and 6 mice, respectively, developed mild arthritis, while only 3 and 4 individuals, respectively, developed more severe arthritis. At the end of the experiment, the cumulative number of hits per experimental day was calculated for each test group. After immunization with 25 pg of bovine 39 kDa whey protein, a maximum of 27 hits was achieved after 30 days, after which a definite decline was observed. When immunized with lower doses of bovine 39 kDa whey protein, the animals had a slightly lower arthritis “score” than mice induced with the 25 pg dose. Although the number of hits was lower, the “relapsing” nature of the arthritis course was observed in all groups. In PBS-treated control mice, we observed a slight and transient swelling of the forelimb. This phenomenon was also observed in untreated, non-injected animals. The average daily cumulative swelling value in these mouse groups reached an average value of 3.4 and was taken as the biological background. In conclusion, bovine 39 kDa whey protein (25, 5, 1 and 0.2 pg doses) is able to induce progressive arthritis in female Balb / c mice. The chronic nature of bovine 39 kDa whey protein-induced arthritis, characterized by periodic relapses and symmetry of affected joints, resembles the disease course of rheumatoid arthritis (RA). Table 5 Initiation and progression of arthritis with bovine 39 kDa whey protein in Balb / c mice Sensitization (n=10) Arthritis onset Arthritis symptoms MV HV none mild severe 0.2 pg B 39 kDa whey protein -,-,-,14,18 8,14,14,14,18, 18,18,18,30,54 0 6 4 1 pg B 39 kDa whey protein 7 7 7 7_7 8,12,12,16,18 8,8,8,8,8, 8,14,16,18,18 0 7 3 5 pg B 39 kDa whey protein 7 7 7 7 7 8,10,10,12,14 16,16,18,20,30 8,8,10,12,12 0 0 10 5 pg B 39 kDa whey protein -,-,-,-,12 8,8,10,12,12 14,14,18,18,20 0 1 9 MV: forelimb. Arthritis symptoms: none: score=0; mild: score less than 2 per animal; severe: score >3 per animal. SEQUENTIALIST DATA FOR SEQUENCING IDENTIFICATION NUMBER 1: LENGTH: 42 amino acids TYPE: amino acid NUMBER OF STRANDS: one TOPOLOGY: linear MOLECULE TYPE: peptide DESCRIPTION OF SEQUENCE IDENTIFICATION NUMBER 1: Tyr 1 Ly s Le u Val Cy s 5 Tyr Tyr Thr Ser Trp 10 Ser Gin Tyr Arg Glu 15 Gly Asp Gly Ser Cys Phe Pro Asp Al a Leu As p Arg Phe Leu Cy s Thr Hi s 20 25 30 Ile Ile Tyr Ser Phe Al a Asn He Ser Asn As p 35 40 DATA OF SEQUENCE IDENTIFICATION NUMBER 2: SEQUENCE CHARACTERISTICS: LENGTH: 383 amino acids TYPE: amino acid NUMBER OF STRANDS: double HU 221 348 Bl TOPOLOGY: linear MOLECULE TYPE: cDNA DESCRIPTION OF SEQUENCE IDENTIFICATION NUMBER 2: Me t Gly Leu Arg Al a Al a Gin Thr Gly Phe Val Val Leu Va 1 Leu Leu 1 5 10 1 5 Gin Ser Cys Al a Al a Tyr Lys Leu Ile Cys Tyr Tyr Thr Ser Trp Ser 20 25 30 Gin Tyr Arg Glu Gly As p Gly Ser Cy s Phe Pro As p Al a I 1 e As p Pro 35 40 45 Phe Leu Cy s Thr Hi s Va 1 I le Tyr Ser Phe Al a Asn I 1 e Ser Asn Asn 50 55 60 Glu Ile As p Thr Trp Glu Trp Asn As p Va 1 Thr Leu Tyr As p Thr Leu 65 70 75 80 Asn Thr Leu Ly s As n Arg Asn Pro Asn Leu Ly s Thr Leu Leu Ser Va 1 85 90 95 Gly Gly Trp Asn Phe Gly Ser Gin Arg Phe Ser Ly s I 1 e Al a Ser Lys 100 105 110 Thr Arg Ser Arg Arg Thr Phe Ile Ly s Ser Va 1 Pro Pro Phe Leu Arg 115 120 125 Thr Hi s Gly Phe As p Gly Leu As p Leu Al a Trp Leu Tyr Pro Gly Trp 130 135 140 Arg As p Ly s Arg Hi s Leu Thr Thr Leu Val Ly s Glu Me t Ly s Al a Glu 145 150 155 160 Phe Va 1 Arg Glu Al a Gin Al a Gly Thr Glu Gin Leu Leu Leu Ser Al a 165 170 175 Al a Va 1 Pro Al a Gly Ly s Ile Al a Ile As p Arg Gly Tyr As p Ile Al a 180 185 190 Gin I 1 e Ser Arg Hi s Leu As p Ph e Ile Ser Le u Leu Thr Tyr As p Phe 195 200 205 Hi s Gly Al a Trp Arg Gin Thr Val Gly Hi s Hi s Ser Pro Leu Phe Arg 210 215 220 Gly Gin Glu Asp Al a Ser Ser Asp Arg Phe Ser Asn Al a Asp Tyr Al a 225 230 235 240 Va 1 Ser Tyr Me t Leu Arg Leu Gly Al a Pro Al a As n Ly s Leu Val Me t 245 250 255 Gly Ile Pro Thr Phe Gly Arg Ser Tyr Thr Le u Al a Ser Ser Ly s Thr 260 265 270 As p Va I Gly Al a Pro I 1 e Ser Gly Pro Gly Ile Pro Gly Gin Phe Thr 275 280 285 Ly s Glu Ly s Gly Ile Leu Al a Tyr Tyr Glu Ile Cy s Asp Phe Leu Hi s 290 295 300 Gly Al a Thr Thr Hi s Arg Phe Arg Asp Gin Gin Val Pro Tyr Al a Thr 305 310 315 320 Ly s Gly Asn G1 n Trp Val Al a Tyr Asp As p Gin Glu Ser Val Ly s Asn 325 330 335 Ly s Al a Arg Tyr Le u Lys Asn Arg Gin Leu Al a Gly Al a Me t Val Trp 340 345 350 Al a Leu As p Leu As p As p Ph e Arg Gly Thr Phe Cys Gly Gin Asn Leu 355 360 365 Alá Phe Pro Leu Thr Ser Al a Ile Lys Asp Va 1 Leu Al a Glu Val 370 375 380 DATA OF SEQUENCE IDENTIFICATION NUMBER 3: SEQUENCE CHARACTERISTICS: LENGTH: 1152 base pairs TYPE: nucleic acid NUMBER OF STRANDS: single TOPOLOGY: linear MOLECULE TYPE: cDNA DESCRIPTION OF SEQUENCE IDENTIFICATION NUMBER 3: HU 221 348 B1 ATGGGGCTGA GGGCGGCTCA GACAGGTTTT GTGGTCCTGG TGCTGCTCCA GAGCTGTGCT 60 GCATACAAGC TGATCTGCTA CTACACCAGC TGGTCCCAGT ACCGGGAGGG TGATGGGAGC 120 TGCTTCCCAG ACGCCATCGA CCCCTTCCTG TGCACCCATG TCATCTACAG CTTTGCCAAC 180 TAAGCAACA ATGAGATCGA CACCTGGGAG TGGAATGACG TGACGCTCTA TGACACACTG 240 AACACACTCA AGAACAGGA CCCCAACCTG AAGACCCTCC TATCTGTTGG AGGAGAAC 300 TTCGGTTCTC AAAGATTTTC CAAGATAGCT TCCAAGACCC GGAGTCGCAG GACTTTCATC 360 AAGTCGGTGC CACCATTTCT GCGGACCCAT GGCTTTGATG GACTGGACCT AGCATGGCTC 420 TACCCCGGGT GGAGACAA GCGGCATCTC ACCACTCTGG TCAAGGAAAT GAAGGCTGAG 480 TTTGTAAGGG AAGCCCAAGC AGGCACAGAG CAGCTTCTGC TCAGTGCAGC AGTACCTGCA 540 GGGAAGATTG CTATTGACAG AGGCTATGAC ATCGCCCAGA TATCCCGACA CCTGGACTTC 600 ATCAGCCTTT TGACCTATGA CTTTCACGGA GCCTGGCGCC AGACAGTCGG ACACCACAGC 660 CCCCTGTTTC GAGGCCAGGA AGATGCAAGT TCTGACAGAT TCAGTAACGC TGACTACGCT 720 GTGAGCTACA TGCTGAGGCT GGGGGCTCCA GCCAATAAGC TGGTGATGGG TATCCCCACT 780 TTTGGGAGGA GCTACACTCT GGCCTCTTCC AAGACAGATG TGGGAGCCCC CATCTCAGGG 840 CCAGGAATTC CAGGCCAGTTCACCAAGGAG AAAGGGATCCC TTGCCTATTA TGAGATCTGT 900 GACTTCCTCC ACGGAGCCAC CACCCACAGA TTCCGTGACC AGCAGGTCCC CTATGCCACC 960 AAGGGCAACC AGTGGGTGGC GTATGACGAC CAGGAGAGTG TCAAAAA GGCACGGTAC 1020 CTGAAGAACA GGCAGCTGGC TGGCGCCATG GTGTGGGCCC TGGACTTGGA TGACTTCCGG 1080 GGCACCTTCT GTGGGCAGAA CCTGGCCTTT CCTCTCACAA GTGCCATCAA AGATGTGCTT 1140 GCTGAGGTGT AG 1152

Claims

CLAIMS 1. A T-cell tolerance-inducing protein comprising an amino acid sequence having at least 70% homology to the amino acid sequence YKLVCYYT SWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (SEQ ID NO: 1), for use as a therapeutic agent.

2. Any of the following proteins for use as therapeutic agents: porcine heparin-binding 38 kDa protein, bovine 39 kDa whey protein, human YKL-39 protein, mouse breast regressing 39 kDa protein (brp39), human fallopian tube-specific glycoprotein, mouse fallopian tube-specific glycoprotein, hamster fallopian tube-specific glycoprotein, bovine fallopian tube-specific glycoprotein, human chitotriosidase precursor protein, and mouse YM-1 secretory protein precursor and fragments thereof.

3. A pharmaceutical composition comprising one or more proteins having an amino acid sequence that is at least 70% homologous to the amino acid sequence YKLVCYYTSWSQ YREGDGSCFPDALDRFLCTHIIYSFANISND (SEQ ID NO: 1), and a pharmaceutically acceptable carrier.

4. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and one or more of the following proteins: porcine heparin-binding 38 kDa protein, bovine whey protein 39 kDa, human YKL-39 protein, mouse breast regressing 39 kDa protein (brp39), human fallopian tube-specific glycoprotein, mouse fallopian tube-specific glycoprotein, hamster fallopian tube-specific glycoprotein, bovine fallopian tube-specific glycoprotein, human chitotriosidase precursor protein, and mouse YM-1 secretory protein precursor and fragments thereof.

5. Use of a protein comprising an amino acid sequence showing at least 70% homology to the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (ID No. 1) for the preparation of a pharmaceutical composition for inducing specific T-cell tolerance against a homologous autoantigen in animals suffering from T-cell-mediated cartilage damage.

6. Use of one or more of the following proteins for the manufacture of a pharmaceutical composition for inducing specific T-cell tolerance to a homologous autoantigen in animals suffering from T-cell-mediated cartilage damage: porcine heparin-binding 38 kDa protein, bovine 39 kDa whey protein, human YKL-39 protein, mouse breast regressing 39 kDa protein (brp39), human fallopian tube-specific glycoprotein, mouse fallopian tube-specific glycoprotein, hamster fallopian tube-specific glycoprotein, bovine fallopian tube-specific glycoprotein, human chitotriosidase precursor protein, and murine YM-1 secretory protein precursor and fragments thereof.

7. Use of a protein comprising an amino acid sequence showing at least 70% homology with the amino acid sequence YKLVCYYTSWSQYREGDGSCFPDALDRFLCTHIIYSFANISND (ID No. 1) for inducing arthritis in an experimental animal for medical research, preferably a mouse.

8. Use of bovine 39 kDa whey protein or human YKL-39 protein for inducing arthritis in an experimental animal for medical research, preferably a mouse.

9. Use of animals suffering from arthritis induced by the use according to claim 7 or 8, for screening new drugs for the treatment of arthritis, preferably for the treatment of rheumatoid arthritis.