Comparisons of HLA-B*3501–restricted, IPSI peptide–specific vs HLA A*0201– restricted, NLV peptide–specific T cells as to their avidity for cognate peptide loaded on autologous DCs and their capacity to lyse autologous CMV-infected DCs. CMV-specific CTLs were incubated for 16 hours with autologous DCs loaded with10-fold serial dilutions of CMV-pp65 subpools containing the HLA A0201 peptide epitope NLVPMVATV or the HLA B3501 epitope IPSINVHHY. IFN-γ expression was then assessed by using an intracellular cytokine assay: (A) Representative flow cytometric analysis after stimulation of NLV or IPS-specific T cells with serial dilutions of cognate peptide. (B) Peptide dose–response curves for the experiment shown in panel A. (C) Chromium-51 release assay showing specific lysis by HLA-B35–restricted CTLs and HLA-A02–restricted CTLs of autologous DCs infected or not with the TB40E endotheliotropic clinical strain of HCMV. E:T, effector-to-target ratio.