Prime-boost vaccine regiment increases breadth of Gag-specific IFN-γ T-cell responses. Breadths of specific IFN-γ responses were analyzed with PBMCs isolated from animals after AdC6 (20 weeks, open bars) and after AdC7 (10 weeks, black bars) immunizations by ELISpot assays using peptide matrices. AdC6, AdC vector derived from serotype 6; AdC7, AdC vector of serotype 7; IFN-γ, interferon-γ PBMC, peripheral blood mononuclear cell.