Search

Some rare HIV-1 -infected individuals, referred to as HIV controllers (HIC), have persistently undetectable plasma viral load in the absence of therapy. This control of HIV-1 replication has been associated with a strong, multifunctional specific CD8+ T cell response. However, no direct link between this immune response and the control of viremia has so far been provided. We investigated parameters of specific CD8+ T cell response and in vitro susceptibility to HIV-1 infection in 11 HIC. We found high frequencies of HIV-specific CD8+ T cells. Interestingly, these cells expressed the activation marker HLA-DR but not CD38. This unique phenotype differentiates HIV-specific CD8+ T cells from HIC and noncontroller subjects and likely reflects a high potential to expand upon exposure to antigen and a capacity to exert effector functions. Accordingly, although CD4+ T cells from HIC were fully susceptible to HIV-1 superinfection, their CD8+ T cells effectively suppressed HIV-1 infection. Remarkably, this potent anti-HIV activity was observed without prior stimulation of CD8+ T cells. This activity was not mediated by secreted inhibitory factors but was due to the elimination of infected CD4+ T cells and was observed only with autologous CD4+ T cells, indicating an HLA-restricted cytotoxic mechanism. This constitutive antiviral capacity of CD8+ T cells could account for the control of viral replication in HIC. [ABSTRACT FROM AUTHOR]