Prevention of experimental autoimmune encephalomyelitis in Lewis rats by treatment with an anti-rat CD5 antibody (OX19).

Treatment of Lewis rats with a single dose of OX19 antibody, specific for rat CD5, uniformly prevented the development of experimental autoimmune encephalomyelitis (EAE). This protective effect had several notable characteristics: (1) it persisted for at least 10 days; (2) it could be achieved with either high doses of the antibody (> 200 micrograms) or lower doses (100-200 micrograms), which did not deplete T cell populations; and (3) the treated animals were able to mount comparable T cell responses to both myelin basic protein and myelin-unrelated antigens. In addition, antibody treatment consistently prevented the development of adoptively transferred EAE, suggesting that enhanced suppressor cell activity may have contributed to the protection. Antibodies such as OX19 appear capable of blocking the development of EAE, and perhaps other autoimmune diseases as well.