| First Author | Vance RE | Year | 1999 |
| Journal | J Exp Med | Volume | 190 |
| Issue | 12 | Pages | 1801-12 |
| PubMed ID | 10601355 | Mgi Jnum | J:66316 |
| Mgi Id | MGI:1928260 | Doi | 10.1084/jem.190.12.1801 |
| Citation | Vance RE, et al. (1999) Recognition of the class Ib molecule Qa-1(b) by putative activating receptors CD94/NKG2C and CD94/NKG2E on mouse natural killer cells. J Exp Med 190(12):1801-12 |
| abstractText | The heterodimeric CD94/NKG2A receptor, expressed by mouse natural killer (NK) cells, transduces inhibitory signals upon recognition of its ligand, Qa-1(b), a nonclassical major histocompatibility complex class Ib molecule. Here we clone and express two additional receptors, CD94/NKG2C and CD94/NKG2E, which we show also bind to Qa-1(b). Within their extracellular carbohydrate recognition domains, NKG2C and NKG2E share extensive homology with NKG2A (93-95% amino acid similarity); however, NKG2C/E receptors differ from NKG2A in their cytoplasmic domains (only 33% similarity) and contain features that suggest that CD94/NKG2C and CD94/NKG2E may be activating receptors. We employ a novel blocking anti-NKG2 monoclonal antibody to provide the first direct evidence that CD94/NKG2 molecules are the only Qa-1(b) receptors on NK cells. Molecular analysis reveals that NKG2C and NKG2E messages are extensively alternatively spliced and approximately 20-fold less abundant than NKG2A message in NK cells. The organization of the mouse Cd94/Nkg2 gene cluster, presented here, shows striking similarity with that of the human, arguing that the entire CD94/NKG2 receptor system is relatively primitive in origin. Analysis of synonymous substitution frequencies suggests that within a species, NKG2 genes may maintain similarities with each other by concerted evolution, possibly involving gene conversion-like events. These findings have implications for understanding NK cells and also raise new possibilities for the role of Qa-1 in immune responses. |
