Influence of KIR diversity on human immunity.

Killer cell immunoglobulin-like receptors (KIR) are expressed on natural killer (NK) cells and on subpopulations of T cells, mostly CD8 cells, that have memory phenotype. KIR thus have the potential to contribute to both the innate immune response, through the action of NK cells, and the adaptive immune response, through the action of memory T cells. KIR were first defined functionally in the context of alloreactive human NK cells that showed specificity for polymorphic HLA class I determinants. Identified in this manner were inhibitory KIR with specificity for HLA-A, B and C determinants. Cloning of cDNA for these IUR led to the identification of additional KIR, some of which are activating receptors with HLA class I specificity and others including both inhibitory and activating KIR for which ligands have yet be defined (reviewed in [I]).