Natural killer cell activation and inhibition by receptors for MHC class I

Several recent advances have been made in our understanding of the mechanisms which human natural killer cells recognize MHC class I molecules. Three are of special relevance: the identification of a novel molecule (DAP1 2) with a key role in the activation pathways; the observation that certain immunoglobulin-like receptors for HLA class I molecules are also utilized by other leucocyte lineages; and the definition of MHC class Ib proteins (i.e. HLA-E and Qa-1b) as specific ligands for the phylogenetically conserved CD94-NKG2 lectin-like receptors.