CLONING OF IMMUNOGLOBULIN-SUPERFAMILY MEMBERS ASSOCIATED WITH HLA-C AND HLA-B RECOGNITION BY HUMAN NATURAL-KILLER-CELLS

Cytotoxicity by natural killer (NK) cells is inhibited by major histoc ompatibility complex (MHC) class I molecules on target cells. This inh ibition may be mediated by NK receptors with different MHC specificiti es. A family of four NK-specific complementary DNAs (cDNAs), designate d NKATs (NK-associated transcripts), was identified that encoded relat ed transmembrane proteins, characterized by an extracellular region wi th two or three immunoglobulin-superfamily domains and by a cytoplasmi c domain with an unusual antigen receptor activation motif (ARAM). The distribution of these cDNAs was clonotypic and correlated with NK cel l inhibition by particular class I alleles. Thus, NKAT cDNAs may encod e receptors for class I molecules on NK cells.