Representative ex vivo antigen-specific responses of KIR3DL1+CD8+ T cells from HLA-Bw6 subjects and representative ex vivo response to P815/anti-CD3 stimulation. Freshly-isolated PBMC from three KIR3DL1 homozygous HIV-infected individuals defined as HLA-Bw6 (a, b, c) and one uninfected KIR3DL1 homozygous individual co-expressing HLA-Bw4 were incubated with overlapping peptides from CMV pp65 (a, c) or HIV Gag (b) as described in the methods. Freshly-isolated PBMC from an uninfected KIR3DL1 homozygous individual who co-expressed HLA-Bw4 were incubated with P815 cells and anti-CD3 as described in the methods section (d). Intracellular IFN-γ production was assessed by flow cytometry with gating on CD3+CD8+ (a, b, c) or CD8+ lymphocytes (d). Unstimulated controls, including PBMC incubated with P815 cells without anti-CD3 (d) are shown in the left hand panel of each set.