Allergic encephalomyelitis induced in guinea pigs by a peptide from the NH2-terminus of bovine P2 protein.

Abstract

Experimental allergic neuritis (EAN) is an inflammatory demyelinating disease of the peripheral nervous system (PNS) first described by Waksman and Adams1,2 in rabbit, guinea pig and mouse after injection of PNS antigen in Freund's complete adjuvant. In rabbit and mouse, the histological lesions were confined to the PNS but the guinea pig reacted curiously to PNS antigens by developing lesions in the central nervous system (CNS) as well as the PNS. Experimental allergic encephalomyelitis (EAE), the CNS counterpart of EAN, is known to be a response to CNS myelin basic protein. In early experiments3,4, basic proteins from PNS myelin also produced a disease in guinea pigs characterised by CNS lesions. Characterisation of the proteins of PNS myelin demonstrated the presence of a basic protein (P1) which was similar to the encephalitogenic basic protein of CNS myelin5. At first it seemed that the CNS lesions were being caused by this (P1) protein. However, immunological studies from our laboratories suggested that when guinea pigs were sensitised to PNS myelin, the resulting lesions were a response to the small PNS myelin basic protein (P2) and not to the P1 protein6. In a preliminary report7, we indicated that a peptide fraction derived from the P2 protein could produce a disease in guinea pigs characterised by CNS lesions. Sequence studies under way in our laboratory now enable us to report that this response is being caused by a tryptophan-containing 20-residue peptide (CN3) derived from the NH2-terminal segment of the bovine P2 protein.