Gross L, Schidlovsky G, Feldman D, Dreyfuss Y, Moore L A
Proc Natl Acad Sci U S A. 1975 Aug;72(8):3240-4. doi: 10.1073/pnas.72.8.3240.
C-type virus particles were found on electron-microscopic examination in placentas from two out of four young healthy Sprague-Dawley rats. One of these specimens contained virus particles budding from the plasma membranes of cells in the junctional zone of the placenta, i.e., the region where the fetal and maternal cell layers meet. In the other placenta, immature and mature C-type virus particles were found among cell debris also in the junctional region. This observation adds another species of animals to those recently reported, such as rhesus and baboon monkeys, as well as humans, in which C-type virus particles were found in the placenta. The presence of C-type viicant in view of the fact that a considerable number of these animals develop spontaneously a variety of malignant tumors, occasionally also leukemia and malignant lymphomas; however, none of these spontaneous tumors reveals the presence of virus particles on electron-microscopic examination. The nature of virus particles detected in rat placenta remains to be determined. As a working hypothesis, it is possible to assume that they may represent the passage of latent, presumably oncogenic, viruses transmitted "vertically" from parents to offspring. In the course of this passage some of them may be formed, emerging temporarily from their latency, before losing their identity and being again incorporated into the cell genetic components.
在对4只健康的幼年斯普拉格-道利大鼠的胎盘进行电子显微镜检查时，在其中2只的胎盘中发现了C型病毒颗粒。其中一个样本中的病毒颗粒从胎盘交界区细胞的质膜上芽生出来，即胎儿和母体细胞层相遇的区域。在另一个胎盘中，在交界区的细胞碎片中也发现了未成熟和成熟的C型病毒颗粒。这一观察结果使在胎盘中发现C型病毒颗粒的动物种类又增加了一种，最近报道的还有恒河猴、狒狒以及人类。鉴于相当数量的这些动物会自发发生多种恶性肿瘤，偶尔也会发生白血病和恶性淋巴瘤，C型病毒颗粒的存在值得关注；然而，在电子显微镜检查中，这些自发肿瘤均未显示出病毒颗粒的存在。在大鼠胎盘中检测到的病毒颗粒的性质仍有待确定。作为一个可行的假设，可以假定它们可能代表潜伏的、大概具有致癌性的病毒“垂直”从亲代传递给子代的过程。在这个传递过程中，其中一些病毒颗粒可能会形成，暂时从潜伏状态中出现，然后失去其特性并再次整合到细胞遗传成分中。
