Virology Unit, Infectious Disease Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health, Shah Alam 40170, Malaysia.
Center for Toxicology and Health Risk Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur 50300, Malaysia.
Int J Mol Sci. 2024 Sep 30;25(19):10541. doi: 10.3390/ijms251910541.
Comprehending the replication kinetics of SARS-CoV-2 variants helps explain why certain variants spread more easily, are more contagious, and pose a significant health menace to global populations. The replication kinetics of the Malaysian isolates of Alpha, Beta, Delta, and Omicron variants were studied in the Vero E6 cell line. Their replication kinetics were determined using the plaque assay, quantitative real-time PCR (qRT-PCR), and the viral growth curve. The Beta variant exhibited the highest replication rate at 24 h post-infection (h.p.i), as evidenced by the highest viral titers and lowest viral RNA multiplication threshold. The plaque phenotypes also varied among the variants, in which the Beta and Omicron variants formed the largest and smallest plaques, respectively. All studied variants showed strong cytopathic effects after 48 h.p.i. The whole-genome sequencing highlighted cell-culture adaptation, where the Beta, Delta, and Omicron variants acquired mutations at the multibasic cleavage site after three cycles of passaging. The findings suggest a strong link between the replication rates and their respective transmissibility and pathogenicity. This is essential in predicting the impacts of the upcoming variants on the local and global populations and is useful in designing preventive measures to curb virus outbreaks.
了解 SARS-CoV-2 变体的复制动力学有助于解释为什么某些变体更容易传播、更具传染性，并对全球人口构成重大健康威胁。在 Vero E6 细胞系中研究了马来西亚分离株的 Alpha、Beta、Delta 和 Omicron 变体的复制动力学。使用噬斑测定法、定量实时 PCR（qRT-PCR）和病毒生长曲线来确定它们的复制动力学。Beta 变体在感染后 24 小时（h.p.i）表现出最高的复制率，这一点可以从最高的病毒滴度和最低的病毒 RNA 倍增阈值中得到证明。斑块表型也在变体之间有所不同，其中 Beta 和 Omicron 变体分别形成最大和最小的斑块。所有研究的变体在感染后 48 小时都会出现强烈的细胞病变效应。全基因组测序突出了细胞培养适应，其中 Beta、Delta 和 Omicron 变体在传代三次后在多碱性切割位点获得了突变。研究结果表明，复制率与其各自的传染性和致病性之间存在很强的联系。这对于预测即将出现的变体对当地和全球人口的影响以及设计预防措施遏制病毒爆发非常重要。
