EFFECTS OF VACCINATION WITH T-CELL RECEPTOR-PEPTIDES - EPITOPE SWITCHING TO A POSSIBLE DISEASE-PROTECTIVE DETERMINANT OF MYELIN BASIC-PROTEIN THAT IS CROSS-REACTIVE WITH A TCR BV PEPTIDE

Immunization of Lewis rats with guinea-pig myelin basic protein (Gp-MB P) induced T cell responses to primary and secondary encephalitogenic determinants, as well as to a third non-encephalitogenic epitope, resi dues 55-69. This sequence is of interest due to its protective activit y against experimental autoimmune encephalomyelitis. Protection involv ed induction of MBP-55-69-specific T cells expressing cross-reactive T CR BV8S6 genes that activated regulatory T cells specific for TCR BV8S 2 determinants expressed on encephalitogenic T cells. We here present and discuss new evidence suggesting a possible immunological crossreac tivity between the protective Gp-MBP-55-69 peptide and the regulatory BV8S2-39-59 peptide. This crossreactivity, which may also occur betwee n the human MBP-55-74 peptide and the BV12S2-38-58 sequence, has poten tially important implications for human diseases such as multiple scle rosis.