HL A- G属于一种非经典 HL A- I类抗原 ,主要表达于母胎界面的滋养层细胞。迄今为止的研究表明 ,HL A- G分子可以与相应杀伤细胞抑制性受体 (killer inhibitory receptor,KIR)作用 ,抑制 NK细胞和 CTL 的杀伤作用 ,这可能是诱导和维持母胎耐受的一个重要机制。与经典 I类分子类似 ,HL A- G的凹槽结构可结合九肽抗原 ,从而可能向 TCR提呈抗原或直接与 T细胞表面 KIR结合 ,进而调控 T细胞功能 HL A-G belongs to a non-classical HLA class I antigen that is mainly expressed in trophoblast cells at the maternal-fetal interface. So far, studies have shown that HL-G molecules can act with the corresponding killer inhibitory receptor (KIR) and inhibit the killing effect of NK cells and CTL, which may be an important factor in inducing and maintaining maternal-fetal tolerance mechanism. Similar to classical class I molecules, the grooved structure of HL-G binds to the nonapeptide antigen, which may present an antigen to the TCR or directly bind to the KIR on the T cell surface, thereby regulating T cell function