Since the above results revealed that CD11c+ CD8+ T cells were a highly activated population with lower PD-1 expression, we further investigated the functional signatures of secretion (IFN-γ, IL-2, and TNF-α) and cytotoxicity (CD107a, granzyme B, and perforin) during HIV-1 infection (Figure 4A). The gene discussed is PDCD1; the disease is HIV-1 infection.