HLA-I-restricted ASP epitopes are recognized by CD8+ T cells during HIV-1 infection. (A) PBMCs isolated from HIV-1 seropositive patients and seronegative donors were stimulated ex vivo with ASP-YL9 in an IFN-γ ELISpot assay. An HCV irrelevant and HIV Gag-derived HLA-A*02-restricted (Gag-SL9) peptide was used as negative and positive controls, respectively. Dotted line indicates a mean threshold of peptide responders (4 times background, 90 SFU/106 PBMCs). Four HLA-A*02+ HIV+ patients had responses to ASP-YL9 (n = 49, right panel), whereas no IFN-γ secretion was detected in HLA-A*02- HIV+ patients (n = 30, middle panel) or HLA-A*02+ seronegative donors (SN, n = 7, left panel). (B) Frequencies of ASP-YL9-, or Gag-SL9- responders according to each group are shown. (C) As in (B) with the ASP-TL10 peptide and a CMV-derived (pp65) peptide. Three HLA-B*07+ HIV+ donors were responding to ASP-TL10 (n = 27, right panel), whereas no responses were detected in HLA-B*07- seropositive donors (n = 27, middle panel) and HLA-B*07+ SN (n = 5, left panel). (D) Frequencies of donors responding to ASP-TL10, HIV Gag (Gag-B7) or CMV (pp65) are indicated according to each group.