Recognition of rheumatoid arthritis synovial antigen by CD4+,CD8? T cell clones established from rheumatoid arthritis joints

OBJECTIVE: To investigate the rheumatoid arthritis (RA)-specific autoantigen(s) recognized by CD4+ T cells in patients with RA. METHODS: CD4+,CD45RO+ T cell clones were established from the joints of RA patients, and were examined for their proliferative response to synovial cells. RESULTS: Eight of 146 T cell clones responded to RA synovial cells in a DR-restricted manner. These T cell clones recognized solubilized antigens extracted from RA synovial cells in the presence of DR-matched antigen-presenting cells, but did not respond to those extracted from non-RA synovial cells. The antigens had a molecular weight of 50/25 kd. Five of the 8 T cell clones used T cell receptor BV6, and the remaining clones used BV12.2. CONCLUSION: The antigens recognized by joint-infiltrating CD4+ T cells are present exclusively in RA synovial cells. The expression of these antigens by synovial cells may trigger the autoreactivity of T cells in RA joints.