The binding ability of 23 overlapping peptides, all derived from the CB11 fragment of CII, was tested on several HLA-DR molecules associated or not with disease susceptibility. These experiments were performed on a variety of cells expressing different HLA-DR molecules, using both indirect and direct binding assays. The CII (256-271) fragment was shown to bind to a restricted population among which the HLA-DR molecules associated with susceptibility to rheumatoid arthritis. The results also clearly indicate that the binding specificity of CII (256-271), among the DR4 molecules, is controlled by the nature of the HLA-DR molecule beta-chain residues 71 and 74, residues previously shown by X-ray crystallography to be involved in the HLA-DR/peptide interaction. The human CII (256-271) peptide is thus likely to play a role in the disease process.

Transformation of human T cells by herpesvirus saimiri allows the production of an unlimited number of T cells which express a functional T-cell receptor. In this study we transformed four T-cell lines derived from rheumatoid arthritis synovial membranes. The transformed T cells were mainly CD4+ and expressed the phenotype of activated T cells. They were grown for more than 1 year in the absence of mitogen or feeder cells, and three of them could be maintained without exogenous IL-2. The presence of viral DNA in the transformed cells was shown by in situ hybridization with a probe from the H-DNA region of the virus. No infectious virus could be recovered from the transformed cells. The relative proportion of the 24 different Vbeta families between the four transformed lines showed variations that increased with time. In the two T-cell lines transformed at an early stage of culture, the Vbeta2 family was maintained at about 10%. The dominant Vbeta2 clones that previously have been characterized in the patient were found in all transformed T-cell lines. We have thus shown the feasibility of obtaining transformed T cells from synovial membranes. They contain the dominant clones that are considered of potential importance for the disease, permitting further functional studies.

Attempts to evaluate the protective effect of live attenuated SIV vaccine strains have yielded variable results depending on the route of immunization, the level of attenuation, the level of divergence between the vaccine candidate and the challenge. The protective mechanisms induced by these vaccines are still not well understood. In an effort to address whether the diversity of the CD4+ T cell repertoire in cynomolgus macaques plays a role in the immunological protection following SIVmacC8 infection, we have performed a longitudinal follow-up of the CD4 repertoire by heteroduplex tracking assay in macaques mock infected or infected with either the attenuated SIVmacC8 or its homologous SIVmacJ5 and challenged with simian-human immunodeficiency virus (SHIV89.6P). Viral load and CD4 absolute counts were determined in these animals and the presence of SHIV89.6P virus in challenged animals was evaluated by PCR and serology. In all macaques that were protected against the challenging virus, we demonstrated a reduced diversity in the CD4+ TRBV repertoire and a few dominant CD4+ T cell clones during early primary infection. In contrast, CD4 TRBV repertoire in unprotected macaques remained highly diverse. Moreover, some of the CD4 T cell clones that were expanded during primary SIV infection re-emerged after challenge suggesting their role in protection against the challenging virus. These results underline the importance of maintaining the CD4 T cell repertoire developed during acute infection and point to the restriction of the CD4 response to the vaccine as a correlate of protection.