The article discusses the functional characteristics of HIV-specific CD8+ T cells, highlighting their ability to produce antiviral cytokines but their impaired cytolytic function. Using a combination of tetramer staining and intracellular cytokine staining, the study assessed the functional heterogeneity of antigen-specific CD8+ T cells in HIV-infected individuals. It found that most HIV-specific CD8+ T cells produce antiviral cytokines like IFN-γ and MIP-1β in response to antigen, but they express significantly lower levels of perforin compared to CMV-specific CD8+ T cells. This reduced perforin expression is linked with persistent CD27 expression, indicating impaired maturation. As a result, HIV-specific CD8+ T cells show lower ex vivo killing activity compared to CMV-specific cells from the same donor. The study also found that HIV-specific CD8+ T cells are not affected by HAART treatment in terms of cytokine secretion. The differences in maturation markers between HIV-specific and CMV-specific CD8+ T cells suggest that HIV-specific cells are at an earlier stage of maturation. These findings indicate that while HIV-specific CD8+ T cells can produce antiviral cytokines, their impaired cytolytic function may limit their ability to control HIV replication. The study provides insights into the functional characteristics of HIV-specific CD8+ T cells and highlights the importance of understanding their role in viral control.The article discusses the functional characteristics of HIV-specific CD8+ T cells, highlighting their ability to produce antiviral cytokines but their impaired cytolytic function. Using a combination of tetramer staining and intracellular cytokine staining, the study assessed the functional heterogeneity of antigen-specific CD8+ T cells in HIV-infected individuals. It found that most HIV-specific CD8+ T cells produce antiviral cytokines like IFN-γ and MIP-1β in response to antigen, but they express significantly lower levels of perforin compared to CMV-specific CD8+ T cells. This reduced perforin expression is linked with persistent CD27 expression, indicating impaired maturation. As a result, HIV-specific CD8+ T cells show lower ex vivo killing activity compared to CMV-specific cells from the same donor. The study also found that HIV-specific CD8+ T cells are not affected by HAART treatment in terms of cytokine secretion. The differences in maturation markers between HIV-specific and CMV-specific CD8+ T cells suggest that HIV-specific cells are at an earlier stage of maturation. These findings indicate that while HIV-specific CD8+ T cells can produce antiviral cytokines, their impaired cytolytic function may limit their ability to control HIV replication. The study provides insights into the functional characteristics of HIV-specific CD8+ T cells and highlights the importance of understanding their role in viral control.