Studies on the refractoriness to reinduction of experimental allergic encephalomyelitis in Lewis rats that have recovered from one episode of the disease.

Lewis rats immunized with myelin basic protein (MBP) in Freund's complete adjuvant (FCA) suffer from a single episode of paralysis from which they recover spontaneously and become refractory to induction of further episodes of paralysis by reimmunization with MBP in FCA. We show that there is a transient period immediately after recovery when a second episode of paralysis can be induced in some animals by reimmunization with MBP in FCA, or soluble MBP prior to the development of complete refractoriness. We also show that rats that are refractory to the induction of experimental allergic encephalomyelitis (EAE) by active immunization with MBP in FCA are also refractory to the adoptive transfer of EAE by in vitro-activated MBP-primed lymphocytes.