【作者】 林羿；

【导师】 曾耀英；

【作者基本信息】 暨南大学 ， 妇产科学， 2002， 博士

【摘要】 妊娠免疫耐受机理是生命科学和医学的研究热点之一。这一机理的阐明，对不孕症、流产和先兆子痫等妇产科疾病的深入诊断和治疗，对组织移植免疫排斥机理的深入研究等，均具有十分重要的意义。 在一定意义上，胎儿是一种特殊的异基因或半异基因移植物，然而却能被母体免疫系统所耐受。这种免疫耐受现象的详细机理，目前还远远没有阐明。 CBA/J和DBA/2是两种比较常用的小鼠近交品系。与DBA/2雄鼠交配的CBA/J雌鼠(CBA/J×DBA/2交配组合)具有易患反复自然性流产的特点，可以用作研究反复自然性流产的动物模型。毫无疑问，以此模型为基础的研究，对于逐步阐明妊娠耐受机理具有重要意义。 针对妊娠免疫耐受机理已经有大量的研究。在某些反复自然流产妇女和某些所谓着床失败型不孕症患者，即经过3次或以上体外受精 一胚胎移植治疗均失败的不孕症患者外周血中，发现NK细胞表面 ＊＊69分于的表达水平与正常生育力妇女相比显著升高。＊＊69是一种 活化型表面标志，它能够激发 NK细胞的细胞毒作用。在 CBA／J X。DBA／2小鼠模型中，母一胎交界面N］C细胞表面CD69分子的表达模 式如何？这种模式是否与胚胎和鼠仔的预后有关？文献检索结果，未 见到这方面的报道。 CD是 lgG FC片段的一种受体（FCR Y Ill）。在人类外周血 NK 细胞中，绝大多数属于 CD ＋型，而在人蜕膜上则仅有一小部分 NK 细胞表达 CD分子。不仅如此，在反复流产患者子宫内膜 NK细胞 群中，CD十型细胞比率也显著升高。因而研究者认为，CD的过 高表达对妊娠有害。然而这种分于在 CBA／J X DBA／2小鼠母一胎界面 NK细胞表面的表达模式尚未见研究。 另外，在组织和器官移植研究中曾经发现：CD80或CD86分于的 单一表达，就可以引起强有力的移植物排斥反应，而阻断这些分子的 表达，即使短暂阻断，也能显著延长移植物存活时间。在某些病例甚 至可以诱导移植物免疫耐受。然而，CD80和CD86等所谓共刺激分子 （或称辅助刺激分子、协同刺激分子）是否参与 CBA／J X DBA／2小鼠 模型中母体对胚胎的排斥机理？文献检索结果，未见到这方面的报道。 目前普遍接受的观点认为：Thl型细胞因子，例如IFN—Y和TNF、一口等对妊娠结局有害，而ThZ型细胞因子，例如 IL—10和 IL—6等 则对妊娠结局有利。在 CBA／J X DBA／2小鼠模型中，一方面，注射 Thlj 型细胞因子可以诱发流产；另一方面，缺乏ThZ型细胞因子也可以导 2 致胚胎吸收率升高。相反，有些研究者却发现，在人类和某些哺乳动 物中，滋养层细胞和妊娠子宫在自然状态下就可以产生 Th型细胞因 子，并且这些细胞因子对维持正常妊娠可能具有重要意义。小鼠胚胎 所产生的某些 Th型细胞因子可能通过与其在子宫内膜上的受体结合 而参与着床过程。由此可见，在妊娠子宫可能存在 Th和 ThZ型反应 之间的平衡，这种平衡是成功妊娠所必需的。 有些研究者发现，人类和某些哺乳动物的精子、卵细胞和配子对 子宫局部的细菌脂多糖门ipopolysacchride，LPS）及其诱导产生的Thl 型细胞因于有抵抗力。这种抵抗力在一定程度上可以保护配子和胚胎， 免遭交配过程所引入的细菌及其可能产生的毒素所引起的母体免疫反 应的杀伤。 既然注射 IFN—Y和 TNF一。能够导致 CBA／J X DBAjZ小鼠的胚 胎吸收，并且另有研究发现，多种T细胞亚群可能参与这一模型的流 产机理，那么这一过程的上游和下游事件又是什么呢？T细胞亚群在 母一胎免疫耐受机理中是否与NK细胞、巨噬细胞等存在相互联系？ 这些问题目前均尚不清楚。 以往研究显示，高水平的血清抗精子抗体不仅与不孕症有关，而 且与某些反复自然流产过程有关。然而，CBA／J X DBA／2小鼠的反复 胚胎吸收是否由于血清中存在抗精于抗体所致？就我们所知，目前尚。无这方面的报道。 有的研究者认为，CBA／J X DBA／2小鼠胎盘的免疫调节功能发生 了改变，这种改变与其反复流产有关。而如果CBAjJ雌鼠曾与BALB儿 3 雄鼠交配，井有h次以上怀孕史，更多还原

【Abstract】 The mechanism of pregnancy tolerance is a hot point of life science and medicine. It will be helpful, as for the clarification of this mechanism, not only to the diagnosis and treatment of infertility, abortion and pre-eclampsia, but also to the research on tissue or organ transplantation.To some extent, fetus is a kind of special allogeneic or semi-allogeneic transplantation. Nevertheless, it is tolerated by maternal immune system. The mechanism responsible for this phenomenon is poorly understood.CBA/J and DBA/2 are among the most commonly used inbred mice. DBA/2 male mated CBA/J female (CBA/J X DBA/2 mating combination) is characterized by abortion-prone. Therefore, it is capable of serving as an animal model of recurrent spontaneous abortion. Undoubtedly, studiesbased on this model will be necessary to clarify the mechanism ofpregnancy tolerance step by step.Numerous studies have been undertaken to address the mechanisms of pregnancy tolerance. Elevated expression of CD69 was found on peripheral blood NK cells in women with recurrent spontaneous abortions and infertility of implantation failures after 3 or more in vitro fertilization and embryo transfer (IVF-ET) cycles, as compared to normal fertile controls. CD69 is an activation marker and it triggers NK cytotoxicity. What’s the pattern of CD69 expression on NK cells at the fetomaternal interface in CBA/J X DBA/2 mice? And whether it is associated with the outcomes of murine fetuses and pups? It remains unanswered so far as we know.CD 16 is a kind of receptor for Fc portion of IgG (FcR Y III). The great majority of human peripheral blood NK cells are CD16+, while only a smaller percentage of human decidual NK cells express CD 16. Moreover, an increased proportion of CD 16+ NK cells were found on endometrial NK cells from recurrent aborters. Thus, reporters proposed that over-expressed CD 16 may be harmful to pregnancy. However, it remains unclear as for the pattern of CD 16 expression on NK cells at the fetomaternal interface in CBA/J X DBA/2 mice.Furthermore, in the cases of tissue or organ transplantation, researchers have shown that expression of either CD80 or CD86 alone is sufficient to support vigorous allograft rejection, whereas blocking both13molecules, even transiently, greatly prolongs allograft survival and in some models can induce transplantation tolerance. However, whether these costimulator molecules, i.e. CD80 and CD86, involve in the mechanisms by which maternal immune responses reject the embryos in CBA/JX DBA/2 mice model? It remains to be answered so far as we know.It is commonly accepted that Thl type cytokines such as IFN- Y and TNF- a are harmful to pregnancy, whereas Th2 type cytokines such as IL-10 and IL-6 are helpful. Researchers have shown that, on one hand, systemically administration of Thl type cytokines induces fetal death or increases fetal resorption. On the other hand, the deficiency of Th2 type cytokines results in the increase of resorption rate in CBA/JX DBA/2 model. In contrast, some reporters suggest that in humans and other mammals, Thl type cytokines are naturally produced by the trophoblast and the pregnant uterus, and these cytokines have been speculated to be important to normal pregnancy. In mice, some embryo-derived Thl type cytokines may be involved in implantation by binding to its receptor expressed on endometrium. Therefore, a balance may be critical during pregnancy between Thl type and Th2 type responses.Some researchers found that, in humans and other mammals, sperm, oocytes and gametes are tolerant to local lipopolysacchride (LPS) callenge, including LPS-induced Thl type cytokines and, to some extent, this mechanism protects gametes and conceptuses from maternal response to14mating-introduced bacteria and their potential endotoxins.Now that some stuyies suggested that the administration of IFN- Y and TNF-a can result in resorptions in CBA/JX DBA/2 model, while other studies shown that a variety of T cell subpopulations seems to be involved in the mechanisms更多还原