Representative secondary antigen-specific responses of KIR3DL1+CD8+ T cells following in vitro stimulation and expansion. Freshly-isolated PBMC from 2 HLA-Bw4+ HIV-infected individuals were cultured for 7 days with specific HLA-A2-restricted flu (a) or HIV-Gag peptides (b), restimulated with peptide-pulsed autologous BLCL as described in the methods section, and tested for antigen-specific IFN-γ production by intracellular flow cytometry with gating on CD3+CD8+ lymphocytes. Cells expressing KIR3DL1 were positively selected from freshly isolated PBMC of an uninfected HLA-Bw4 individual, incubated with a specific HLA-A2-restricted CMV peptide for 7 days, restimulated with peptide-pulsed autologous BLCL as described in the methods section, and tested for antigen-specific IFN-γ production by intracellular flow cytometry with gating on CD3+CD8+ lymphocytes (c).