Mechanisms of recovery and acquired resistance in Lewis rat experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis in the Lewis rat is an acute, self-limiting disease. Rechallenge of convalescent rats fails to induce disease. Previous experiments provided direct evidence against clonal deletion as the mechanism of recovery from disease and resistance to reinduction and suggested the operation of an active suppression mechanism. The present studies on the mechanism(s) of recovery and resistance suggest (1) resistance is a function of a systemic rather than a local suppressor mechanism, (2) suppression acts by inhibiting induction of immunity rather than expression of immunity and (3) recovery from disease can occur in the absence of detectable anti-myelin basic protein antibodies, yet these antibodies may play a role in protection against reinduction of disease.