KIR/HLA: genetic clues for a role of NK cells in the control of HIV.

Early events following HIV infections determine the course of disease progression. Mounting evidence suggests that antiviral immune responses induced soon after infection, prior to the induction of adaptive immune responses, are key to early control of viral infection. Among the early innate immune effector cells, natural killer (NK) cells represent a unique subset of lymphoctyes that do not express an antigen specific receptor. Rather, these cells integrate signals from an arsenal of non-specific inhibitory and activating receptors that are expressed on their cell surface. As such, these cells are classified as cells of the innate immune system, and they are able to lyse certain tumor targets and infected cells without the need for prior antigen sensitization. Over the past decade, accumulating evidence suggests that these innate lymphocytes may not be as innate as once believed, but that individual NK cell clones may show some target cell specificity, and play a critical early role following infection with HIV.