DETECTION OF VIRUSES IN CELL SUBSTRATES

CBER感兴趣的是细胞系是否用于产品生产 包含病毒或类似病毒的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 近年来，卵巢(CHO)细胞系被用作细胞底物 获得许可的组织型纤溶酶原激活剂激活酶和其他重组 在CHO细胞中制造的产品目前正在IND的临床试验中。 CHO细胞含有电子可见的内源性逆转录病毒样颗粒 显微镜。这些颗粒不具传染性，也不能证明 逆转录酶活性，并被认为类似于 小鼠细胞底物中常见的脑池内A颗粒 用于生产单抗。一项电子显微镜研究是 因此用来确定生长因子或细胞因子 (可能是在CHO细胞中产生的)可能会影响这些内源性 粒子。结果表明，颗粒含量从30%-100%增加到 几种细胞因子(GM-CSF、干扰素、肿瘤坏死因子)对CHO细胞的作用 佛波酯TPA。一份手稿最近发表在 体外毒理学(1991)。我们目前正在检查Sf9细胞(一种 用于生产杆状病毒重组产物的昆虫细胞系 表达系统)可被虫媒病毒感染。十二种虫媒病毒 已经被选中，目前正在接受测试，以确定他们是否有能力 在Sf9细胞中感染或维持；到目前为止，已测试的两个 显然可以感染SF9细胞并通过以下途径转移到Vero细胞 共培养或通过过滤上清液。除了斑块之外 滴定，培养物正在电子显微镜下检查。

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.