Experimental allergic encephalomyelitis: basic protein regions responsible for delayed hypersensitivity

Three separate peptide regions were isolated from the chymotrypsin digest of the encephalitogenic basic protein from bovine myelin of the central nervous system. The peptides induced delayed type hypersensitivity (DTH) and elicited delayed skin reactivity in experimental animals. However, none of the isolated peptides was capable of inducing experimental allergic encephalomyelitis (EAE). The amino acid sequence of peptide CTP-3 (Gly-Ala-Glu-Gly-Gln-Lys-Pro-Gly-Phe-OH) and peptide CTP-la were found to overlap the C-terminal sequence of encephalitogenic peptides E (residue 112–125) and T8 (residue 65–74) of the basic protein, respectively. The third DTH inducing peptide, CB1-T1, (N-Acetyl-Ala-Ser-Ala-Gln-Lys-OH) was found to overlap the N-terminal sequence of the basic protein molecule. Common to the three DTH inducing peptides, to the basic protein and to the encephalitogenic peptides E-S and T8S is the X-X-X-Gln-Lys sequence. Isolation of the regions of the basic protein that are responsible for DTH provides antigens for the study of the mechanism of cellular immunity in EAE.