Materno-foetal cell traffic by DNA finger printing and its biological Significance

我们以前曾报道，免疫孕鼠与T-依赖性抗原成功地诱导抑制抗原特异性空斑形成细胞（PFC）在后代中的相关抗原的反应。这种抑制不是由于施用的抗原、怀孕母亲产生的抗体或哺乳转移，而是依赖于完整的母体T细胞的存在。它是MHC限制性方式耐受，并能维持至少1/6的小鼠寿命。传统观点认为，胎盘是一个天然屏障，不允许细胞通过。然而，我们得到的结果强烈地表明，母体T细胞通过胎盘，然后诱导耐受。在这个研究项目中，我们试图通过使用分子技术来证实母体细胞在胎儿循环中的存在。我们已经发现，一个高度多态性的微卫星序列内的H-2复合体的II类Eb基因是非常有用的各种H-2等位基因的分子检测。为了追踪婴儿脾脏中母亲H-2等位基因，采用了DNA多态性分析方法。主要步骤包括对来自小鼠基因组DNA的H-2特异性微卫星DNA序列进行PCR扩增和RFLP分析。结果表明，免疫孕鼠的母体T细胞通过胎盘进入胎鼠体内，诱导子代产生抗原特异性免疫耐受。

We have previously reported that the immunization of pregnant mice with T-dependent antigens successfully induced suppression of the antigen-specific plaque forming cell (PFC) response to the relevant antigens in the offspring. This suppression was not due to the administered antigens, the antibodies produced by the pregnant mother, or lactational transfer, but was dependent on the presence of the intact maternal T cells. It was MHC-restricted manner tolerance and was able to continue at least 1/6 of the murine life. In traditional point of view, the placenta would act as a natural barrier and not allow the cells to pass through. However, the results we got strongly suggested that maternal T cells go through the placenta and then induce the tolerance. In this research project, we try to substantiate the presence of maternal cells in the fetal circulation through the use of molecular techniques. We have found that a highly polymorphic microsatellite sequence within the class II Eb gene of the H-2 complex is quite useful for the molecular detection of various H-2 alleles. For tracking maternal H-2, alleles in baby spleens, the method of DNA polymorphic analysis was carried out. The main procedure involved the PCR-amplification and RFLP analysis of the DNA sequence encompassing the H-2 specific microsatellite from the genomic DNA of baby mice. The results indicated that maternal T cells of immunized pregnant mice go through the placenta and into the fetal bodies, induce the antigen specific immunological tolerance in the offspring.