KIR3DL1-Negative CD8 T Cells and KIR3DL1-Negative Natural Killer Cells Contribute to the Advantageous Control of Early Human Immunodeficiency Virus Type 1 Infection in Homozygous Individuals.

homozygosity in human leukocyte antigen class B alleles has been associated with a delayed acquired immunodeficiency syndrome (AIDS) development and better control of human immunodeficiency virus type 1 (HIV-1) viral load (VL) than homozygosity. Efficient CD8 T cell and natural killer (NK) cell functions have been described to restrain HIV-1 replication. However, the role of KIR3DL1 expression on these cells was not assessed in -homozygous participants infected with HIV-1 CRF01_A/E subtype, currently the most prevalent subtype in China. Here, we found that the frequency of KIR3DL1-expressing CD8 T cells of individuals homozygous for [1.53% (0-4.56%)] was associated with a higher VL set point (Spearman  = 0.59,  = 0.019), but this frequency of KIR3DL1CD8 T cells [1.37% (0.04-6.14%)] was inversely correlated with CD4 T-cell count in individuals homozygous for ( = -0.59,  = 0.011). Moreover, CD69 and Ki67 were more frequently expressed in KIR3DL1CD8 T cells in individuals homozygous for than ( = 0.046 for CD69;  = 0.044 for Ki67), although these molecules were less frequently expressed in KIR3DL1CD8 T cells than in KIR3DL1CD8 T cells in both groups (all  < 0.05). KIR3DL1CD8 T cells have stronger p24-specific CD8 T-cell responses secreting IFN-γ and CD107a than KIR3DL1CD8 T cells in both groups (all  < 0.05). Thus, KIR3DL1 expression on CD8 T cells were associated with the loss of multiple functions. Interestingly, CD69NK cells lacking KIR3DL1 expression were inversely correlated with HIV-1 VL set point in -homozygous individuals ( = -0.52,  = 0.035). Therefore, KIR3DL1CD8 T cells with strong early activation and proliferation may, together with KIR3DL1CD69NK cells, play a protective role during acute/early HIV infection in individuals homozygous for . These findings highlight the superior functions of KIR3DL1CD8 T cells and KIR3DL1CD69NK cells being a potential factor contributing to delayed disease progression in the early stages of HIV-1 infection.