DETECTION OF VIRUSES IN CELL SUBSTRATES

CBER感兴趣的是用于产品生产的细胞系是否 含有病毒或病毒样颗粒或病毒核酸序列，或 支持对人类具有传染性的病毒的生长。 中国仓鼠 卵巢（CHO）细胞系被用作最近的细胞基质， 获得许可的组织纤溶酶原激活剂Activase和其他重组体 CHO细胞生产的产品目前正在IND下进行临床试验。 CHO细胞含有电子可见的内源性逆转录病毒样颗粒 显微镜 这些颗粒不具有传染性， 逆转录酶活性，并被认为是类似于 脑池内A颗粒通常存在于使用的小鼠细胞基质中 用于单克隆抗体生产。 一项电子显微镜研究 因此，进行了确定是否生长因子或细胞因子 （可能在CHO细胞中生产）可能会影响这些内源性 粒子 结果表明，颗粒增加了30-100%， 用几种细胞因子（GM-CSF、IFN、TNF）或用 佛波醇酯TPA。一份手稿最近发表在《 体外毒理学（1991年）。 我们目前正在研究是否Sf 9细胞（一种 用于在杆状病毒中产生重组产物的昆虫细胞系 表达系统）可被虫媒病毒感染。 十二虫媒病毒 目前正在测试他们的能力， 感染或维持在Sf 9细胞中;迄今为止， 显然可以感染SF 9细胞，并转移到Vero细胞， 共培养或通过过滤的上清液。除了斑块 滴定，培养物正在通过电子显微镜检查。

It is of interest to CBER whether cell lines used for product production contain virus or virus-like particles or viral nucleic acid sequences or support the growth of viruses infectious for humans. The Chinese Hamster Ovary (CHO) cell line is used as the cell substrate for the recently licensed tissue plasminogen activator Activase, and additional recombinant products made in CHO cells are currently in clinical trials under IND. CHO cells contain endogenous retroviral-like particles visible by electron microscopy. These particles are not infectious and do not demonstrate reverse transcriptase activity, and are thought to be similar to the intracisternal A particles commonly found in mouse cell substrates used for monoclonal antibody production. An electron microscopic study was therefore undertaken to determine whether growth factors or cytokines (which might be manufactured in CHO cells) might affect these endogenous particles. The results indicate increases in particles from 30-100% after treatment of CHO cells with several cytokines (GM-CSF, IFN, TNF) or with the phorbol ester TPA. A manuscript has recently been published in In Vitro Toxicology (1991). We are currently examining whether Sf9 cells (an insect cell line used to produce recombinant products in the Baculovirus expression system) can be infected by arboviruses. Twelve arboviruses have been selected and are currently being tested for their ability to infect or be maintained in Sf9 cells; to date two of those tested apparently can infect SF9 cells and be transferred to Vero cells by cocultivation or via filtered supernatants. In addition to plaque titration, cultures are being examined by electron microscopy.