SIV Gag D205E, but not V63A mutation abrogates recognition of CD4+ T cells restricted by alternate MHC-II molecules. A) Comparison of recognition of wild type SIVmac239 Gag57-71CG15 and the mutant peptide containing the V63A point mutation or DRB1*06 (bottom panel). Flow data are shown as IFN-γ versus TNF-α, and percentages are cytokine-positive cells. B) Comparison of recognition of wild type SIVmac239 Gag197-211QA15 and Gag197-211QA15 bearing the D205E point mutation (highlighted in grey and bold) by Gag197-211QA15-specific CD4+ T cells restricted by either DRB*W4:01 (top panel) or DRB1*03:06 (bottom panel). All data shown are representative of 3 or more independent single replicate experiments.