The sudden emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the end of 2019 from the Chinese province of Hubei and its subsequent pandemic spread highlight the importance of understanding the full molecular details of coronavirus infection and pathogenesis. Here, we compared a variety of replication features of SARS-CoV-2 and SARS-CoV and analysed the cytopathology caused by the two closely related viruses in the commonly used Vero E6 cell line. Compared to SARS-CoV, SARS-CoV-2 generated higher levels of intracellular viral RNA, but strikingly about 50-fold less infectious viral progeny was recovered from the culture medium. Immunofluorescence microscopy of SARS-CoV-2-infected cells established extensive cross-reactivity of antisera previously raised against a variety of non-structural proteins, membrane and nucleocapsid protein of SARS-CoV. Electron microscopy revealed that the ultrastructural changes induced by the two SARS viruses are very similar and occur within comparable time frames after infection. Furthermore, we determined that the sensitivity of the two viruses to three established inhibitors of coronavirus replication (remdesivir, alisporivir and chloroquine) is very similar, but that SARS-CoV-2 infection was substantially more sensitive to pre-treatment of cells with pegylated interferon alpha. An important difference between the two viruses is the fact that – upon passaging in Vero E6 cells – SARS-CoV-2 apparently is under strong selection pressure to acquire adaptive mutations in its spike protein gene. These mutations change or delete a putative furin-like cleavage site in the region connecting the S1 and S2 domains and result in a very prominent phenotypic change in plaque assays.

中文翻译：

---

SARS冠状病毒2在Vero E6细胞中的复制：复制动力学，快速适应性和细胞病理学。

湖北省在2019年底突然出现严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）及其随后的大流行蔓延，凸显了了解冠状病毒感染和发病机理的完整分子细节的重要性。在这里，我们比较了SARS-CoV-2和SARS-CoV的多种复制特征，并分析了常用Vero E6细胞系中由两种密切相关的病毒引起的细胞病理学。与SARS-CoV相比，SARS-CoV-2产生更高水平的细胞内病毒RNA，但从培养基中回收的感染性病毒后代却少了约50倍。SARS-CoV-2感染细胞的免疫荧光显微镜检查建立了先前针对多种非结构蛋白产生的抗血清的广泛交叉反应性，SARS-CoV的膜和核衣壳蛋白。电子显微镜显示，由两种SARS病毒诱导的超微结构变化非常相似，并在感染后相当的时间内发生。此外，我们确定了两种病毒对三种已建立的冠状病毒复制抑制剂（雷姆昔韦，阿拉泊韦和氯喹）的敏感性非常相似，但SARS-CoV-2感染对用聚乙二醇化干扰素预处理细胞的敏感性更高α。两种病毒之间的一个重要区别是，在传给Vero E6细胞后，SARS-CoV-2显然处于强大的选择压力下，需要在其刺突蛋白基因中获得适应性突变。