Experimental autoimmune uveitis in the athymic nude rat.

A single injection of the retinal soluble antigen (S-Ag, 30 micrograms) to the Lewis or the heterozygous (rnu/+) rats induces a severe bilateral uveitis, characterized initially by infiltration of the retina with inflammatory cells. The athymic nude rat (homozygous rnu/rnu), which lacks the thymus gland and T cell-mediated functions, does not develop ocular inflammatory disease, clinically of histologically, after repeated challenges with S-Ag. Circulating anti-S-Ag antibodies were found in S-Ag-immunized Lewis rats and in the heterozygous, but not the athymic nude rats. Good proliferative responses to concanavalin A, S-Ag and purified protein derivitive of tuberculin (PPD) were found in lymphocyte cultures prepared from the draining lymph nodes of immunized heterozygous rats, but not when lymphocytes from the athymic nude rats were used. Uveitis could be induced in the athymic nude rat when lymphocytes from S-Ag-immunized heterozygous rats were transferred to them. By stimulating the donor lymphocytes in vitro with S-Ag before transfer, the number of recipients that developed uveitis was increased. On the other hand, it was impossible to transfer disease with hyperimmune serum alone. The possible role of T lymphocytes in the induction of experimental autoimmune uveitis with S-Ag is discussed.