Rojo S, Burshtyn D N, Long E O, Wagtmann N
Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
J Immunol. 1997 Jan 1;158(1):9-12.
The MHC class I-specific inhibitory receptors on human and mouse NK cells have surprisingly different structures. The mouse receptors (Ly-49) are type II transmembrane glycoproteins of the C-type lectin family, whereas the human receptors (killer cell inhibitory receptors (KIR)) belong to the Ig superfamily. This difference prompted a search for Ig-like inhibitory receptors in mice. Here we show that gp49, a mouse mast cell protein of unknown function but with sequence similarity to KIR, is expressed in NK cells. The gp49 cytoplasmic tail, containing a sequence related to an inhibitory motif shared by KIR and Ly-49, delivered a strong inhibitory signal in both human and mouse NK cells when substituted for a KIR cytoplasmic tail. These data show that Ig-like receptors with inhibitory properties exist in both species and that mouse mast and NK cells may recognize common inhibitory ligands.
人类和小鼠自然杀伤细胞（NK细胞）上的MHC I类特异性抑制性受体结构惊人地不同。小鼠的受体（Ly-49）是C型凝集素家族的II型跨膜糖蛋白，而人类的受体（杀伤细胞抑制性受体（KIR））属于免疫球蛋白超家族。这种差异促使人们在小鼠中寻找免疫球蛋白样抑制性受体。我们在此表明，gp49是一种功能未知但与KIR有序列相似性的小鼠肥大细胞蛋白，在NK细胞中表达。gp49的胞质尾含有一个与KIR和Ly-49共有的抑制基序相关的序列，当替代KIR胞质尾时，在人类和小鼠NK细胞中均传递了强烈的抑制信号。这些数据表明，两种物种中均存在具有抑制特性的免疫球蛋白样受体，并且小鼠肥大细胞和NK细胞可能识别共同的抑制性配体。
