Determinants of Natural Killer Cell Ly49 Receptor Specificity

自然杀伤细胞（NK）是淋巴细胞，作为抵御病毒和肿瘤的第一道防线，摧毁病理改变的细胞。NK细胞表达在健康细胞上普遍表达的I类（CI）主要组织相容性复合物分子特异性抑制受体。由于CI表达缺失（通常发生在病毒感染细胞或肿瘤细胞中），NK抑制受体的缺失释放了对NK细胞的抑制，使它们能够破坏这种改变的细胞。Ly49是主要一类ci特异性受体的大家族，在小鼠和大鼠NK细胞中表达，但在人类中不表达。CI与β -2微球蛋白（b2m）相关，结合并呈现细胞内蛋白水解事件中的肽片段。我们和其他人发现，CI结合肽的身份可以决定Ly49对CI的识别。目前尚不清楚的是，健康细胞中调节NK细胞的内源性肽的性质是什么

Natural killer (NK) cells are lymphocytes that act as a first line of defense against viruses and tumours, destroying pathologically altered cells. NK cells express inhibitory receptors specific for class I (CI) major histocompatiblity complex molecules ubiquitously expressed on healthy cells. Lack of engagement of NK inhibitory receptors, due to loss of CI expression that typically occurs with virus-infected cells or tumour cells, releases inhibition of NK cells, allowing them to destroy such altered cells. Ly49 are large families of major class of CI-specific receptors expressed by mouse and rat NK cells, but not humans. CI associate with beta-2 microglobulin (b2m) and bind and present peptide fragments from intracellular proteolytic events. We, and others, have found that the identity of the CI-bound peptide can determine Ly49 recognition of CI. What is unclear, is the nature of endogenous peptides in healthy cells that regulate NK cells, and the