早期妊娠的免疫耐受机制

胚胎对于母体来说是半异己的移植物 ,其表达部分父系抗原。孕早期母体免疫系统 ,尤其是子宫内膜局部的 NK细胞、巨噬细胞、TCR( γ+ δ+ ) T细胞和 B淋巴细胞等免疫细胞能否识别并耐受胚胎抗原 ,直接影响妊娠结局。近年来的研究表明 ,母体免疫系统在受到体内高浓度性激素水平抑制的基础上 ,通过子宫内膜局部 EAIF、HLA-G等分子产生免疫抑制 ;R80 K、BP和 PIBF等封闭因子产生免疫封闭 ;Fas L和 RCAS1诱导免疫清除 ;降调 CD1、CD80、CD86及增强 IL-1 0表达以诱导克隆无能和 /或非特异性的免疫调节等机制共同作用 ,产生对胚胎抗原的免疫耐受 ,而且这些因素之间存在相互作用 ,其中一种机制失调即引致母体对胚胎的免疫排斥 ,可导致妊娠失败

The Mechanism of Maternal Immunotolerance to Embryo Antigen in Early Pregnancy

Embryo was viewed as a half allograft to mother because of expression of patern al antigen. During early pregnancy, maternal immune system, especially local NK cells, macrophages, TCR (γ +δ +) T cells and B lymphocytes in maternal endom etrium recognized embryo antigen and acquired a tolerance of it determine the pregnancy outcome. Recently, researches reveled that, based on mild immunosuppr ession by high level sex hormone in vivo, maternal immune system can be indu ced to be tolerant of embryo antigen via local immunosuppression by EAIF and HL A-G in uterine, immunological blocking by R80K, Bf and PIBF, immunological clea rance by FasL, RCAS1, immunological anergy by downregulation of CD1, CD80, CD86 and upregulation of IL-10 and/or nonspecific immunoloregulation. Some interacti ons found in those mechanisms and the disturbance of one mechanism can lead to i mmunological rejection to embryo by maternal immune system and result in pregnan cy failure.