Localization of an encephalitogenic epitope for the SJL mouse in the N-terminal region of myelin basic protein.

T cells from SJL mice reactive with myelin basic protein peptide 1-38 have been reported to be encephalitogenic when adoptively transferred into naive syngeneic recipients. To determine whether the encephalitogenic epitope recognized by peptide 1-38-specific SJL T cells was different from those recognized by H-2u-restricted MBP peptide 1-38-specific T cells, peptide 1-38-specific SJL T cell lines were developed following immunization with guinea pig MBP peptide 1-38. Following a period of in vitro selection in the presence of peptide 1-38 and syngeneic antigen-presenting cells, one of two T cell lines transferred severe clinical disease adoptively. The second line was not encephalitogenic. When the fine specificity for antigen of the two T cell lines was determined by the use of overlapping synthetic peptides, the encephalitogenic epitope recognized by the encephalitogenic line was localized to residues 17-27. This epitope is clearly distinct from that recognized by H-2u mice. The non-encephalitogenic line was found to react only with peptide 1-38, and did not react with mouse MBP.