Cyclosporine and dexamethasone inhibit T-lymphocyte MHC class II antigens and IL-2 receptor expression in experimental autoimmune uveitis.

Results of recent studies indicated that a monoclonal ART18 antibody recognizes the receptor sites or closely related structures for IL-2 on activated rat T-cells. The major histocompatibility complex (MHC) class II (Ia) antigens (RT1B and RT1D in rat), detected with OX6 antibody, and OX17 antibody, may be present on activated rat T-cells. In the present report, we examined the effect of corticosteroids and cyclosporine (CsA) on the expression of IL-2 receptors and Ia antigens by the T-cells, which constituted the major cellular component of the ocular infiltration during the period of peak ocular inflammatory activity in experimental autoimmune uveoretinitis (EAU). Lewis rats immunized with retinal S-antigen (S-Ag) and treated for a limited time with suboptimal doses of either CsA or Dexamethasone (Dex) subsequently developed EAU. The inflamed ocular tissues were studied using an immunoperoxidase staining technique. CsA treatment resulted not only in the inhibition of IL-2 receptors on T-cells, but also in the prevention of the induction of Ia antigen expression on T-cells and other non-lymphoid cells. Dex treatment resulted in less inhibition of the expression of both class II antigens and IL-2 receptor by the infiltrating T-cells.