Depletion of gamma/delta T cells does not prevent or ameliorate, but rather aggravates, rat adjuvant arthritis

Objective. To investigate the role of gamma/delta T cells in Mycobacterium tuberculosis-induced rat adjuvant arthritis. Methods. Rats with adjuvant arthritis were injected with the anti-T cell receptor gamma/delta (anti-TCR gamma/delta) monoclonal antibody V65 according to a preventive protocol, a pre-arthritis peak protocol, and a late therapeutic protocol. Arthritis severity and joint destruction were monitored, and depletion of target cells was analyzed by how cytometry. Results. Although all protocols led to successful depletion of TCR gamma/delta(bright) cells in peripheral blood and lymph nodes, none of the regimens influenced clinical parameters of adjuvant arthritis, If rats were treated before the clinical peak of adjuvant arthritis, however, joint destruction was significantly more severe than in vehicle-treated rats. Conclusion. Rat adjuvant arthritis is not promoted or perpetuated by gamma/delta T cells. Aggravation of joint destruction with pre-arthritis peak anti-gamma/delta treatment suggests a stage-dependent protective role of gamma/delta T cells in adjuvant arthritis.