Neubert W J, Hofschneider P H
Virology. 1983 Mar;125(2):445-53. doi: 10.1016/0042-6822(83)90215-5.
The cell line Cl-E-8 showing expression of Sendai-6/94 viral antigens after the original isolation was reexamined after approximately 160 subcultures. In the virus fraction of cell supernatants 6/94 virus particles (termed 6/94 cl) could be demonstrated; no infectivity, however, was monitored. We were also unable to activate the viral infectivity of 6/94 cl virus by trypsin treatment. The analysis of viral RNA revealed that the virus contains a high-molecular-weight (50 S) single-stranded RNA. After cocultivation of Cl-E-8 cells with several standard cell lines the production of an infectious 6/94 virus, termed 6/94 co, was detected. The infectivity titer in the supernatants was very low, about three orders of magnitude lower than in cultures infected with the egg-grown 6/94 virus (6/94 ST). Surprisingly, the production of infectious 6/94 cl virus invariably ceased several subcultures after cocultivation even in the presence of foreign cells. However, the infectivity could be repeatedly reinduced by adding fresh foreign cells.
最初分离后显示仙台-6/94病毒抗原表达的细胞系Cl-E-8在大约160次传代培养后被重新检查。在细胞上清液的病毒部分中可以证明存在6/94病毒颗粒（称为6/94 cl）；然而，未监测到感染性。我们也无法通过胰蛋白酶处理激活6/94 cl病毒的感染性。病毒RNA分析表明该病毒含有高分子量（50 S）单链RNA。在用几种标准细胞系与Cl-E-8细胞共培养后，检测到产生了一种有感染性的6/94病毒，称为6/94 co。上清液中的感染性滴度非常低，比用鸡胚培养的6/94病毒（6/94 ST）感染的培养物低约三个数量级。令人惊讶的是，即使存在外来细胞，共培养后几代，有感染性的6/94 cl病毒的产生总是会停止。然而，通过添加新鲜的外来细胞可以反复重新诱导感染性。
