FIG 4.

SIV Nef-specific CD8 T cell response predicted by linkage analysis. (A) Whole blood from 3 SIV-infected macaques was stimulated by 3 SIV Nef 15-mer peptides spanning the site of a putative Mane-B028-restricted CTL response identified by the MHC-I–SIV mutation linkage analysis. Gated CD3⁺ CD8⁺ lymphocytes were studied for IFN-γ expression, with the 1 Mane-B028-positive macaque showing a positive response and 2 Mane-B028-negative macaques showing no response. SSC, side scatter; FSC, forward scatter. (B) The minimal Nef-specific CTL epitope was mapped to a 9-mer peptide using serial dilutions of overlapping 9- to 11-mer peptides. (C) The putative CTL escape mutation (R to E at position 1) identified in the linkage analysis was evaluated for whether it abrogated CTL recognition.