In the context of NK-cell recognition and killing of HIV+ CD4+ T cells, the NKG2D activating receptor is engaged by cell-surface molecules (NKG2D ligands, NKG2DLs) that are induced during productive HIV infection in T cells, and delivers a potent stimulatory signal resulting in cytotoxicity [42,43,44,45,46]. This evidence concerns the gene KLRK1 and HIV infectious disease.