Farkas Tibor, Aboezz Zeinab R
Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
Viruses. 2024 Nov 28;16(12):1849. doi: 10.3390/v16121849.
Recently, using a panel of recombinant CHO cell lines, we identified the coxsackie and adenovirus receptor (CAR) and histo-blood group antigens (HBGAs) or sialic acid as the minimum requirement for susceptibility to rhesus enteric calicivirus (ReCV) infections. While ReCVs cause lytic infection in LLC-MK2 cells, recombinant CHO (rCHO) cell lines did not exhibit any morphological changes upon infection. To monitor infectious virus production, rCHO cell cultures had to be freeze-thawed and titrated on LLC-MK2 monolayers. This raised the question of whether ReCV infection in rCHO cells is persistent and whether non-enveloped progeny virions are released from the infected cells. Here, we used the rCHO-CAR+ cell line and a CAR and sialic acid-dependent recovirus strain (FT7) and found that these cells were persistently infected, and infectious virus was continuously produced and released into the culture without showing any visible cell damage. Viral capsid protein and replication intermediate double-stranded RNA (dsRNA) were detectable in almost all cells for at least 12 passages. We suspect a fully exosomal viral exit mechanism without a lytic cycle in these cells. rCHO cell may provide a valuable system for ReCV production (producer cell line) and serve as a model for investigating enteric calicivirus non-lytic viral exit mechanisms and the properties of the released, most likely membrane-cloaked, infectious progeny virions.
最近，我们利用一组重组中国仓鼠卵巢（CHO）细胞系，确定了柯萨奇病毒和腺病毒受体（CAR）以及组织血型抗原（HBGAs）或唾液酸是恒河猴肠道杯状病毒（ReCV）感染易感性的最低要求。虽然ReCVs在LLC-MK2细胞中引起裂解感染，但重组CHO（rCHO）细胞系在感染后未表现出任何形态变化。为了监测感染性病毒的产生，rCHO细胞培养物必须进行冻融处理，并在LLC-MK2单层细胞上进行滴定。这就提出了一个问题，即rCHO细胞中的ReCV感染是否持续存在，以及无包膜的子代病毒粒子是否从感染细胞中释放出来。在这里，我们使用了rCHO-CAR+细胞系和一种依赖CAR和唾液酸的重组病毒株（FT7），发现这些细胞被持续感染，感染性病毒不断产生并释放到培养物中，而没有显示出任何可见的细胞损伤。在至少12代的几乎所有细胞中都能检测到病毒衣壳蛋白和复制中间体双链RNA（dsRNA）。我们怀疑在这些细胞中存在一种完全通过外泌体的病毒释放机制，而没有裂解周期。rCHO细胞可能为ReCV的生产提供一个有价值的系统（生产细胞系），并作为一个模型用于研究肠道杯状病毒的非裂解性病毒释放机制以及释放的、很可能被膜包裹的感染性子代病毒粒子的特性。
