CD8A and HIV-1 infection: We performed the polychromatic flow cytometric assay as described above in peptide-stimulated peripheral blood CD8+ T cells derived from the men who have sex with men (MSM) population, and the functionalities of HIV-specific CD8+ T cells were compared between the primarily infected individuals (<6 months) and early chronically infected subjects (12–36 months) to determine the evolution of bulk HIV-specific CD8+ T cell functionality at this early stage of HIV-1 infection.