Evaluation of synthetic peptides from human and macaque Fas for epitope reconstituting activity. (A) Autologous macaque T cells were labeled overnight with 51Cr and pulsed with 1 μg/mL of each of the indicated human Fas 15 or 16-mer peptides, and then used as target cells for Fas-specific CTL clones in a 4-hour cytotoxicity assay. Control target cells included nontransduced autologous T cells alone or pulsed with an irrelevant peptide, the specific human cytomegalovirus pp65 9-mer peptide NLVPMVATV, and autologous T cells transduced with LV'VFas. Data are shown for one representative T-cell clone at the E/T ratios indicated. (B) Autologous macaque T cells were labeled overnight with 51Cr and pulsed 1 μg/mL of the 10-mer peptide HGKKEAYDTLI (♦) corresponding to the human Fas or HGKKDACDTLI (⋄) corresponding to the homologous macaque sequence. Comparable results were obtained with multiple other Fas-specific T-cell clones, and peptide titration experiments indicated that half-maximal lysis was obtained with about 2 to 3 nM HGKKEAYDTLI.
