Protective effects of overexpression TCR Vbeta5.2-HSP70 and TCR Vbeta8.2-HSP70 against collagen-induced arthritis in rats.

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 Vbeta 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 Vbeta5.2 and Vbeta8.2 clonotypes in the joints of CIA rats. In this study, we constructed the recombinant eukaryotic expression vectors pTARGET-TCR Vbeta5.2/8.2-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-gamma 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 Vbeta5.2-HSP70 and pTARGET-TCR Vbeta8.2-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.