Department of Structural Biology, Stanford University, Stanford, California 94305, USA.
Nat Rev Immunol. 2013 Feb;13(2):133-44. doi: 10.1038/nri3370. Epub 2013 Jan 21.
Natural killer (NK) cells have roles in immunity and reproduction that are controlled by variable receptors that recognize MHC class I molecules. The variable NK cell receptors found in humans are specific to simian primates, in which they have progressively co-evolved with MHC class I molecules. The emergence of the MHC-C gene in hominids drove the evolution of a system of NK cell receptors for MHC-C molecules that is most elaborate in chimpanzees. By contrast, the human system of MHC-C receptors seems to have been subject to different selection pressures that have acted in competition on the immunological and reproductive functions of MHC class I molecules. We suggest that this compromise facilitated the development of the bigger brains that enabled archaic and modern humans to migrate out of Africa and populate other continents.
自然杀伤 (NK) 细胞在免疫和生殖方面发挥作用，其功能受可变受体控制，这些受体可识别 MHC Ⅰ类分子。在人类中发现的可变 NK 细胞受体是灵长类动物所特有的，它们与 MHC Ⅰ类分子逐渐共同进化。MHC-C 基因在人科动物中的出现促使 MHC-C 分子的 NK 细胞受体系统进化，在黑猩猩中这一系统最为复杂。相比之下，人类 MHC-C 受体系统似乎受到不同选择压力的影响，这些压力在 MHC Ⅰ类分子的免疫和生殖功能上相互竞争。我们认为，这种妥协促进了大脑的发展，使古人类和现代人类得以走出非洲并移居到其他大陆。
