Effects of bucillamine, a new anti-rheumatic drug, on the experimental autoimmune uveitis in rats.

The in vitro and in vivo effects of a new immunomodulating agent, bucillamine, on experimental autoimmune uveitis (EAU) was studied in the rat. The capacity of S-antigen-sensitized lymphocytes to proliferate in response to the antigen or to produce antigen-specific antibodies was significantly suppressed by bucillamine in culture in a dose-dependent manner. The inhibitory effect of bucillamine was significantly enhanced by adding cyclosporin A (CYA) in the culture. The in vivo effects of bucillamine alone or in combination with CYA were further examined in Lewis rats immunized with S-antigen. All untreated rats developed severe EAU 17 days after S-antigen immunization, while rats treated with either bucillamine (200 mg kg-1 day-1) or CYA (2 mg kg-1 day-1) demonstrated milder symptoms of EAU. A combination therapy with bucillamine (20 or 200 mg kg-1 day-1) and CYA (2 mg kg-1 day-1) exhibited much more significant suppression of EAU induction. Although the in vivo treatment with bucillamine or CYA had no effects on the T-cell populations of spleen cells, the combination therapy significantly decreased the CD4+ T-cell population. As for the immune responses to S-antigen in drug-treated rats, bucillamine suppressed the lymphocyte proliferation to S-antigen, which was further suppressed by combination therapy with CYA. The serum antibody levels specific to S-antigen were not affected by tested dose of bucillamine.