Brain-infiltrating cytolytic T lymphocytes specific for theiler's virus recognize H2D(b) molecules complexed with a viral VP2 peptide lacking a consensus anchor residue

Mice expressing the H2(b) haplotype are resistant to infection with Theiler's murine encephalomyelitis virus (TMEV), which causes chronic demyelination in susceptible mice, The prominent cytolytic T-lymphocyte (CTL) response to the VP2 antigen encoded by TMEV led us to the identification of a class I-binding peptide derived from the VP2 antigen, Escherichia coli transformants overexpressing a series of 11 overlapping VP2 protein fragments mere subjected to lysis and alkali digestion, and the resultant peptide pools were tested for their abilities to sensitize RMA-S targets for lysis by CTLs, The source of effector CD8(+) T cells for the assays was either freshly harvested central nervous system-infiltrating lymphocytes (CNS-IL) of CNS-IL-derived VP2-specific CTL clones and lines, A 10-residue peptide at VP2 positions 121 to 130 (VP2(121-130)(FHAGSLLVFM) was identified that sensitized targets for lysis and formed stable complexes with H2D(b) class I mocules, The VP2(121-130) peptide sensitized target cells for lysis by freshly harvested CNS-IL CTLs at femtomolar concentrations Despite its relative high level of biological activity, the VP2(121-130) peptide is disyinguished from other D-b-binding peptides by its lack of an asparagine residue al position five, which had been previously proposed to be a requirement for D-b-peptide complexing.