胎儿这一同种异体移值物,能在母体内自由地生存,其原因一直被归结为母体免疫功能的降低。由于研究是在不均一的条件下进行的,所以常出现矛盾的结果。整体非特异性免疫抑制不应视为胎儿能在母体内生存的唯一机制。胎儿是生长在免疫系统未遭损伤的母体内,这提示母亲对其胎儿表现出特异性细胞介导的免疫反应。此反应的机制是怎样的?暴露于母体的抗原已观察到在一些无绒毛滋养层组织中,整个妊娠过程都存在着胎儿的Ⅰ类 MHC(主要组织相容性复合体)抗原。表明母体能接触到移植抗原,因此,有可能发生排斥反应。即使在与母体组织血液不接触的绒毛基质和 The fetus, an allograft, can freely live within the mother, the reason has always been attributed to the reduction of maternal immune function. As research is conducted under heterogeneous conditions, conflicting results often appear. Overall non-specific immunosuppression should not be considered as the only mechanism by which the fetus can survive in the mother’s body. The fetus is grown in the uninjured maternal body of the immune system, suggesting that mothers exhibit a specific cell-mediated immune response to their fetus. What is the mechanism of this reaction? Exposure to maternal antigens It has been observed that in some lint-free trophoblastic tissues, fetal MHC Class I (MHC) antigens are present throughout pregnancy. That the mother can have access to transplant antigens, therefore, there may be rejection. Even in villi matrices not in contact with maternal tissue blood and