SIV Gag D205E abrogates the effector function of Gag
QA15-specific CD4+ T cells. A) DRB*W4:01-positive (MHC-II match) or -negative (MHC-II mismatch) macrophages were infected with SIVmac316E for 24 hours, then co-cultured with Gag197-211QA15-specific, DRB*W4:01-restricted CD4+ T cell clones at an E:T of 1:1 for 24 hours. Macrophages were then stained for surface expression of CD14 and intracellular SIV Gag p27. Percentages indicate Gag p27 staining. B) Recognition of uninfected, SIVmac316E-infected, or SIVsmE543-3-infected autologous macrophages by a DRB*W4:01-restricted, Gag197-211QA15-specific CD4+ T cell line. Flow data are shown as IFN-γ versus TNF-α or CD107a, and percentages are cytokine-positive cells. Lower box indicates sequence identity of core Gag199-210AE12 epitope in utilized SIV strains. All data shown are representative of 3 or more independent single replicate experiments.