T-CELL DETERMINANT STRUCTURE OF MYELIN BASIC-PROTEIN IN B1O.PL, SJL J, AND THEIR F(1)S/

Recent experiments have shown that during the course of chronic experi mental allergic encephalomyelitis, there is a shift in the determinant hierarchy away from the dominant to other subdominant and cryptic sel f determinants. It was therefore of interest to define the pattern of dominance for mouse myelin basic protein in the three commonly used ex perimental allergic encephalomyelitis model strains of mice, i.e., B1O .PL, SJL/J, and (SJL x B1O.PL)F-1. Our studies indicate that many cryp tic determinants are demonstrable, which only activate T cells on inje ction as individual peptides and not with the native protein. The core amino acid residues of the various determinants are defined and range in size between 5 and 10 amino acids. Interestingly, there is a bias toward H-2(u)-restricted response vis-a-vis the H-2(s)-restricted resp onse in the (SJL x B1O.PL)F-1 strain. The TCR V beta 8.2 gene segment was not predominantly used for responses to other determinants, althou gh some B1O.PL and (SJL x B1O.PL)F-1 cell lines expressed V beta 8.2 m ore than others. This study represents the most comprehensive analysis so far of the pattern of dominant and cryptic proliferative T cell de terminants and their core sequences for mouse myelin basic protein.