Indeed, uterine-derived NK (uNK) cells (but not pbNK cells) activated in vitro with IL-12 and IL-15, inhibited infection of cell lines, PBMCs, and primary human endometrial cells with strains of HIV that use CXCR4 for cell entry.212 The inhibitory activity was associated with uNK-produced CXCL12, a CXCR4 ligand, and supressed by CXCL12 neutralising antibodies.212 Moreover, dNK cells significantly delayed and reduced infection of decidual macrophages with HIV strains that use CCR5 for entry. This evidence concerns the gene CCR5 and infection.