INFUSION OF SOLUBLE MYELIN BASIC-PROTEIN PROTECTS LONG-TERM AGAINST INDUCTION OF EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS

Protection against experimental autoimmune encephalomyelitis (EAE) ind uced by s.c. infusion of myelin basic protein (MBP) alone is dose depe ndent and long lived. Protection is not effective against passively in duced disease nor is it transferable with lymphoid cells. The prolifer ative response of lymph node cells to MBP following encephalitogenic c hallenge is decreased in the EAE-protected animals as is the productio n of IL-2 and IFN-gamma by these cells. Treatment with soluble MBP pri med rats for antibody production is evidenced by the early appearance of anti-MBP antibody following encephalitogenic challenge. Determinati on of antibody isotype following challenge revealed a change in the ra tio of IgG1 to IgG2a with a significant increase in the amount of IgG1 produced. These data suggest that infusion of high dose soluble neuro antigen primes the immune response such that subsequent challenge with an encephalitogenic inoculum pushes the response down a non-destructi ve Th2 autoimmune pathway.