Suppression of experimental autoimmune encephalomyelitis by the oral administration of myelin basic protein.

The oral administration of myelin basic protein (MBP) to Lewis rats prior to an encephalitogenic challenge resulted in total inhibition or a significant delay in the onset of experimental autoimmune encephalomyelitis (EAE). In vitro lymphocyte proliferative responses to MBP were significantly decreased in MBP-fed rats when compared with vehicle-fed controls. Suppression of EAE and in vitro proliferative responses to MBP were observed to be antigen specific, since oral feeding of a control protein exerted no suppressive effect. Moreover, the specificity of MBP-induced oral tolerance was shown to be species specific, since feeding guinea pig MBP (GPMBP) or human MBP (HuMBP) induced protection only against a GPMBP or HuMBP challenge, respectively. Conversely, Lewis rats could not be orally tolerized to the self antigen rat MBP.