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.
【저자키워드】 Evolution, antiviral drugs, Antisera, RNA synthesis, furin-like cleavage site, plaque phenotype, 【초록키워드】 SARS-CoV-2, Coronavirus infection, coronavirus, pandemic, Mutation, Pathogenesis, Chloroquine, adaptive, SARS-CoV, SARS-COV-2 infection, Infection, Remdesivir, virus, Spike protein, non-structural proteins, nucleocapsid protein, SARS virus, Replication, cross-reactivity, Spread, sensitivity, electron microscopy, Culture, Microscopy, membrane, selection pressure, Viral RNA, molecular, Interferon alpha, Vero E6 cell, inhibitor, change, Coronavirus replication, Vero E6, acute respiratory syndrome, Frame, medium, domain, Chinese, phenotypic, cell line, plaque assays, progeny, feature, Cell, highlight, S1 and S2, caused, subsequent, raised, analysed, less, occur, variety, comparable, related virus, SARS-CoV-2-infected cell, 【제목키워드】 Replication, Vero E6, replication kinetics,