Salcedo M, Bousso P, Ljunggren H G, Kourilsky P, Abastado J P
Unité de Biologie Moléculaire du Gène, INSERM U277, Institut Pasteur, Paris, France.
Eur J Immunol. 1998 Dec;28(12):4356-61. doi: 10.1002/(SICI)1521-4141(199812)28:12<4356::AID-IMMU4356>3.0.CO;2-H.
Recent studies on human NK cells have demonstrated that the NK cell CD94/NKG2 receptors bind to the nonclassical MHC class I molecule HLA-E. A functional CD94/NKG2 complex has not yet been identified in rodents, but cDNA encoding rat and mouse CD94 and NKG2 have recently been cloned, suggesting that CD94/NKG2 receptors may exist in species other than man. The mouse nonclassical MHC class I molecule Qa-1 shares several features with HLA-E. This suggests that Qa-1 may be similarly recognized by murine NK cells. To study the ability of Qa-1 to bind to murine NK cells, we have produced a soluble tetrameric form of Qa-1b. In the present study, we demonstrate that Qa-1b tetramers distinctly bind to a large subset of fresh or IL-2-activated NK1.1+/CD3- splenocytes independently of the expression of Ly49 inhibitory receptors. Binding occurs whether NK cells have evolved in an MHC class I-expressing or in an MHC class I-deficient environment. Our data suggest the existence of a Qa-1-recognizing structure on a large subpopulation of murine NK cells that may be similar to the human CD94/NKG2 heterodimeric complex.
近期关于人类自然杀伤（NK）细胞的研究表明，NK细胞的CD94/NKG2受体可与非经典的MHC I类分子HLA-E结合。在啮齿动物中尚未鉴定出具有功能的CD94/NKG2复合体，但编码大鼠和小鼠CD94及NKG2的cDNA最近已被克隆，这表明CD94/NKG2受体可能存在于人类以外的物种中。小鼠非经典的MHC I类分子Qa-1与HLA-E具有一些共同特征。这表明Qa-1可能会被小鼠NK细胞以类似方式识别。为了研究Qa-1与小鼠NK细胞结合的能力，我们制备了可溶性四聚体形式的Qa-1b。在本研究中，我们证明Qa-1b四聚体可独立于Ly49抑制性受体的表达，与大量新鲜的或经白细胞介素-2激活的NK1.1+/CD3-脾细胞明显结合。无论NK细胞是在表达MHC I类分子的环境中还是在缺乏MHC I类分子的环境中发育，结合都会发生。我们的数据表明，在大量小鼠NK细胞亚群上存在一种可识别Qa-1的结构，其可能类似于人类的CD94/NKG2异二聚体复合体。
