Natural killer cell group 2 member A receptor (NKG2A (CD159a))

Natural killer cell group 2 member A receptor (NKG2A, CD159a) is a type II transmembrane protein and member of the C-type lectin-like receptor family, expressed primarily as a heterodimer with CD94 on human NK cells and some T cell subsets[1][2][5][6]. It functions as an **inhibitory immune checkpoint** receptor by recognizing the non-classical MHC I molecule HLA-E presenting peptides from other MHC I molecules, thus preventing NK cell attack on normal, healthy cells[2][5][6]. Its blockade (e.g. by monoclonal antibodies) is under investigation as a cancer immunotherapy approach, aiming to enhance innate and adaptive immune responses against tumors[5]. The receptor does not directly trigger cytotoxicity, but rather signals through ITIMs (immunoreceptor tyrosine-based inhibitory motifs) in its cytoplasmic domain, mediating a negative regulatory signal to its host cell[1][2][5].

Other names

NKG2ACD94/NKG2ACD159a

Immune checkpoint blockade (monoclonal antibodies block NKG2A to enhance NK and T cell cytotoxicity against tumors)