CD8A and infection: In HIV mono-infected individuals the HIV-specific CD8+ T cell profile consisted of dual cytokine secreting cells IFN-γ+TNF-α+ (38% of total HIV-specific CD8+ T cells) and mono-functional cells (62% of total HIV-specific CD8+ T cells)(Fig. 1G).Bi-functional T cells were found to be present at progressively lower frequencies from HIV mono-infection, to co-infection with LTBI, to co-infection with TB (Fig. 1 G-1).