TNF and infection: Monofunctional IL-2 or TNF-α producing HIV-specific CD8+ T cells were very infrequent in this cohort of chronically infected patients and only a small proportion of HIV-specific CD8+ T cells expressed TNF-α responses confirming previous studies that this effector function is lost early in infection (Lichterfeld et al., 2004; Wherry et al., 2003).