Hunt J S, Andrews G K, Wood G W
J Immunol. 1987 Apr 15;138(8):2481-7.
Very few types of normal cells fail entirely to express class I human leukocyte antigens (HLA), and many of those cells (sperm, fetal amnion epithelial cells, and fetal trophoblasts) are related to the process of reproduction. Susceptibility of sperm to modulation of class I antigens has not been examined, but it has recently been demonstrated that amnion cells respond to exposure to IFN-gamma with readily detectable levels of class I antigens. In addition, one of two trophoblast cell lines (BeWo) has been shown to exhibit enhanced expression of class I HLA in response to IFN-gamma. Expression by a second trophoblast cell line (Jar) was not inducible. Findings in the present study included demonstration of IFN-gamma-enhanced class I-specific mRNA synthesis in JEG-3 cells, which are derived from BeWo, and failure of synthesis by Jar cells. Those results eliminated trivial explanations for the preceding findings and confirmed the responsiveness of some but not all cells of trophoblast origin to IFN-gamma. When successful modulating conditions for amnion and malignant trophoblast cells were applied to normal tissues, third trimester term chorionic cytotrophoblasts and first trimester villous syncytial and cytotrophoblasts failed to exhibit class I HLA. Neither malignant nor normal trophoblasts expressed class II HLA under any condition of testing. Failure of induction of HLA expression by normal trophoblasts could not be attributed to either loss of viability by tissue explants or failure of modulating reagents to reach the trophoblasts. The results demonstrate that regulation of expression of histocompatibility antigens by major populations of normal trophoblasts and one of two choriocarcinoma cell lines differs markedly from that of other fetal and adult cells. Uncommon regulatory mechanisms may be essential to maintenance of the trophoblast as an immunologically inert barrier between the mother and her antigenically disparate fetus.
极少类型的正常细胞完全不表达I类人类白细胞抗原（HLA），而且其中许多细胞（精子、胎儿羊膜上皮细胞和胎儿滋养层细胞）都与生殖过程相关。精子对I类抗原调节的易感性尚未得到研究，但最近已证明羊膜细胞在暴露于γ干扰素后会出现易于检测到的I类抗原水平。此外，已显示两种滋养层细胞系之一（BeWo）在暴露于γ干扰素后会增强I类HLA的表达。而另一种滋养层细胞系（Jar）的表达则不可诱导。本研究的结果包括证明源自BeWo的JEG - 3细胞中γ干扰素增强了I类特异性mRNA的合成，而Jar细胞则未出现合成。这些结果排除了对先前发现的简单解释，并证实了部分但并非所有滋养层来源的细胞对γ干扰素具有反应性。当将成功调节羊膜和恶性滋养层细胞的条件应用于正常组织时，妊娠晚期的绒毛膜细胞滋养层细胞以及妊娠早期的绒毛合体滋养层细胞和细胞滋养层细胞均未表现出I类HLA。在任何测试条件下，恶性和正常滋养层细胞均不表达II类HLA。正常滋养层细胞未能诱导HLA表达，这既不能归因于组织外植体的活力丧失，也不能归因于调节试剂未能作用于滋养层细胞。结果表明，正常滋养层细胞的主要群体以及两种绒毛膜癌细胞系之一对组织相容性抗原表达的调节与其他胎儿和成年细胞明显不同。罕见的调节机制可能对于维持滋养层作为母亲与其抗原性不同的胎儿之间的免疫惰性屏障至关重要。
