Treatment of collagen-induced arthritis in rats with a monoclonal antibody against the alpha/beta T cell antigen receptor.

A monoclonal antibody (MAb) to the alpha/beta T cell receptor (TCR alpha/beta), R73 MAb, completely blocked the induction of collagen-induced arthritis (CIA) in rats when the MAb was administered at the time of immunization with type II collagen. When administered after CIA had begun, the progression of the arthritis was suppressed significantly by R73 MAb treatment. The preventive and suppressive effects of R73 MAb on CIA were associated with the depletion of peripheral blood alpha/beta-positive T cells. These results indicate that alpha/beta-positive T cells play a role in the progression of existing CIA as well as in its induction.