TREATMENT OF MURINE LUPUS WITH MONOCLONAL-ANTIBODIES TO LYMPHOCYTE FUNCTION-ASSOCIATED ANTIGEN-1 - DOSE-DEPENDENT INHIBITION OF AUTOANTIBODY PRODUCTION AND BLOCKADE OF THE IMMUNE-RESPONSE TO THERAPY

Monoclonal antibodies (mAb) to lymphocyte function-associated antigen-1 (LFA-1) have been used successfully in vivo to inhibit immune responses and to block inflammatory reactions. To determine whether these effects of anti-LFA-1 could retard autoimmune disease, we treated lupus-prone NZB/NZW F-1 (B/W) mice with a rat mAb to LFA-1 (anti-CD11a). Mice received high-dose therapy (500 mu g twice weekly), low-dose therapy (40 mu g thrice weekly), or phosphate-buffered saline from age 5 months to age 10 months. Treatment with high doses of anti-CD11a suppressed both the immune response to the rat mAb and the production of autoantibodies to double-stranded DNA. In contrast, treatment with low doses of anti-CD11a elicited an immune response to the rat mAb and did not suppress autoantibody production. The immunosuppressive effects of high doses of anti-CD11a were not due to target cell depletion. In fact, treatment induced a marked lymphocytosis which involved all lymphocyte subsets equally. Despite inhibiting autoantibody production, high-dose therapy had only modest effects on longevity. (C) 1994 Academic Press, Inc.