Collagen-induced arthritis （CIA） is an animal model, which closely resembles human rheumatoid arthritis （RA） in pathogenesis and pathology. Evidence suggests that the inhibition of T lymphocytes or their functions can alleviate the progression of arthritis. So the administration of arthritogenic T cell receptor （TCR） variable region peptide or DNA vaccines encoding pathogenic TCR Vβ variable region may provide useful information for designing specific immunotherapies against autoimmune diseases. Heat shock proteins （HSPs） have the function of raising antigenic immunogenicity and HSP70 has a protective effect against arthritis. We previously demonstrated the presence of pathogenic predominant T cell receptor Vβ5.2 and Vβ8.2 clonotypes in the joints of CIA rats. In this study, we constructed the recombinant eukaryotic expression vectors pTARGET-TCR Vβ5.2/8.2-HSP70, and evaluated their protective effects on CIA rats. Protective effects were observed in CIA rats by injecting these recombinant DNA vaccines, which could alleviate arthritis index, decrease the levels of IFN-~ and anti-CII antibody in serum, and increase the levels of IL-4. Pathological changes were not as serious as those observed in control CIA rats. The rat injected with two combined vaccines showed better protective effects than CIA rats administered with individual vaccine. These results showed that recombinant DNA vaccines pTARGET-TCR Vβ5.2-HSP70 and pTARGET-TCR Vβ8.2-HSP70 could significantly alleviate the arthritic symptoms of CIA rats, and better protective effects could be achieved if these two vaccines were used in combination. Cellular ＆ Molecular Immunology.
Background Arthritogenic T lymphocytes with common T cell receptor （TCR） Vβ clonotypes, infiltrating in the articulars of rheumatoid arthritis （RA） patients, play a central role in the pathogenesis of RA. TCR Vβ5.2 and TCR Vβ8.2 are the main pathogenic T cell clonotypes in the course of collagen-induced arthritis （CIA） progression in Lewis rats. To investigate a TCR-based immunotherapy for RA, we constructed recombinant DNA vaccines encoding TCR Vβ5.2 and TCR Vβ8.2, and evaluated the inhibitive effects of the two vaccines on CIA rats.Methods Genes encoding TCR Vβ5.2 and TCR Vβ8.2 were amplified by RT-PCR from spleen lymphocytes of Lewis rats and cloned into the eukaryotic expression vector pTargeT. The expression of vaccines was confirmed by RT-PCR and immunohistochemistry. The inhibitive effects of the vaccines on articulars of CIA rats were assessed with arthritis index evaluation and histology. Interferon γ （IFN-γ） and interleukin （IL）-4 production by spleen lymphocytes were tested with enzyme-linked immunospot assay （ELISPOT） technique, the changes in peripheral CD4^＋ and CD8^＋ lymphocyte populations were tested by flow cytometry, and the level of anti-CII antibody in serum was assayed by enzyme-linked immunosorbent assay （ELISA）.Results Recombinant DNA vaccines pTargeT-TCR Vβ5.2 and pTargeT-pTCR Vβ8.2 were successfully constructed. Both vaccines inhibited CIA, which alleviated the arthritis index score （P 〈0.05）, decreased the level of IFN-γ （P 〈0.05）, and reduced the ratio of CD4^＋/CD8^＋ lymphocytes （P 〈0.05） and the anti-CII antibody in serum （P 〈0.05）. In addition, the histological change in DNA-vaccinated rats was less serious than CIA rats. Compared to pTCR Vβ 8.2 and pTCR Vβ 5.2 groups, the group that was injected with a combination of the two vaccines showed stronger inhibitive effects on CIA than either individual vaccine.Conclusion The recombinant plasmids pTargeT-TCR Vβ5.2 and pTargeT-TCR Vβ8.2 have obvious inhibatory effec
