HLA class I recognition by killer cell Ig-like receptors

Natural killer (NK) cell activation is regulated by a combination of positive and negative signals coming from repertoires of activating and inhibitory receptors expressed on the surface of each NK cell. Receptors specific for major histocompatibility complex (MHC) class I molecules on ta-get cells inhibit NK effector functions such as cytotoxicity and cytokine production. As reviewed here, the killer cell Ig-like receptor (KIR) family on, human NK cells includes receptors with activating as well as inhibitory potential, receptors that have no known ligand, and inhibitory receptors with well-defined specificities Sor MHC class I such as HLA-B and HLA-C.