Sequence determinants of modified cobra venom neurotoxin which induce immune resistance to experimental allergic encephalomyelitis: Molecular mechanisms for immunologic action

A nontoxic, iodoacetamide-modified cobratoxin derivative (CAM-NTX) induced resistance to experimental allergic encephalomyelitis I(EAE) in guinea pigs . Resistance was retained after trypsin digestion and shown to reside in N- terminal and central peptides of CAM-NTX. A similarly modified protein card iotoxin (CAM-CTX), representative of proteins homologous with cobratoxin, w as not immunosuppressive. Depressed clinical symptoms in EAE-resistant anim als correlated with reduced lymphocytic infiltration of the brain, Antibody to myelin basic protein (MBP) was reduced in immunosuppressed animals. The ;immunoinhibitory determinants in CAM-NTX may mimic immune response suppre ssor proteins (STRS-alpha 7) and the EAE-resistance region of MBP.