King A, Boocock C, Sharkey A M, Gardner L, Beretta A, Siccardi A G, Loke Y W
Research Group in Human Reproductive Immunobiology, Department of Pathology, University of Cambridge, United Kingdom.
J Immunol. 1996 Mar 15;156(6):2068-76.
In this study, evidence is provided that normal human first trimester extravillous trophoblast expresses class I HLA-C molecules in addition to HLA-G. cDNA from highly purified trophoblast cells obtained by flow cytometric sorting was amplified by reverse-transcriptase PCR using HLA locus-specific primers. The identity of the product was confirmed by Southern blotting and hybridization by a second HLA-C-specific oligonucleotide. HLA-C mRNA was clearly demonstrated in all trophoblast samples as well as in JEG-3 and BeWo choriocarcinoma cells. JAR choriocarcinoma cells did not express HLA-C. The presence of HLA-C protein in extravillous trophoblast was investigated using a panel of Abs: L31 is specific for heavy chains of all HLA-C alleles; Q1/28 reacts with all HLA class I products except HLA-G; HC-10 has preferential reactivity with HLA-B and HLA-C heavy chains. We performed 35S metabolic and 125I surface labeling of normal first trimester trophoblast and found abundant HLA-C intracellularly together with low levels of expression of both the beta 2m-associated forms and free heavy chains on the surface. Flow cytometric analysis of normal trophoblast confirmed the expression of a class I HLA molecule distinct from HLA-G by positive reactivity with Q1/28. Immunohistologic studies of first trimester placenta and the implantation site clearly showed expression of HLA-C in all extravillous trophoblast populations. Our results demonstrate the presence of two HLA class I molecules, HLA-G and HLA-C, on the surface of extravillous trophoblast. These results have implications in understanding how maternal uterine lymphocytes, notably the abundant NK-like cells, might recognize the implanting placenta.
在本研究中，有证据表明，正常人类孕早期的绒毛外滋养层除了表达HLA - G外，还表达I类HLA - C分子。使用HLA基因座特异性引物，通过逆转录酶PCR扩增经流式细胞术分选获得的高度纯化的滋养层细胞的cDNA。通过Southern印迹法以及与第二种HLA - C特异性寡核苷酸杂交来确认产物的身份。在所有滋养层样本以及JEG - 3和BeWo绒毛膜癌细胞中均清楚地检测到HLA - C mRNA。JAR绒毛膜癌细胞不表达HLA - C。使用一组抗体研究绒毛外滋养层中HLA - C蛋白的存在情况：L31对所有HLA - C等位基因的重链具有特异性；Q1/28与除HLA - G外的所有HLA I类产物发生反应；HC - 10对HLA - B和HLA - C重链具有优先反应性。我们对正常孕早期滋养层进行了35S代谢标记和125I表面标记，发现细胞内有大量HLA - C，同时表面β2m相关形式和游离重链的表达水平较低。对正常滋养层的流式细胞术分析通过与Q1/28的阳性反应确认了一种不同于HLA - G的I类HLA分子的表达。对孕早期胎盘和着床部位的免疫组织学研究清楚地显示，在所有绒毛外滋养层细胞群中均有HLA - C的表达。我们的结果表明，绒毛外滋养层表面存在两种HLA I类分子，即HLA - G和HLA - C。这些结果对于理解母体子宫淋巴细胞，尤其是大量的NK样细胞如何识别着床胎盘具有重要意义。
