Emerging Microbes and Infections (Dec 2022)

The spike receptor-binding motif G496S substitution determines the replication fitness of SARS-CoV-2 Omicron sublineage

  • Ronghui Liang,
  • Zi-Wei Ye,
  • Chon Phin Ong,
  • Zhenzhi Qin,
  • Yubin Xie,
  • Yilan Fan,
  • Kaiming Tang,
  • Vincent Kwok-Man Poon,
  • Chris Chung-Sing Chan,
  • Xiaomeng Yang,
  • Hehe Cao,
  • Kun Wang,
  • Haoran Sun,
  • Bodan Hu,
  • Jian-Piao Cai,
  • Cuiting Luo,
  • Kenn Ka-Heng Chik,
  • Hin Chu,
  • Yi Zheng,
  • Kwok-Yung Yuen,
  • Jasper Fuk-Woo Chan,
  • Dong-Yan Jin,
  • Shuofeng Yuan

DOI
https://doi.org/10.1080/22221751.2022.2111977
Journal volume & issue
Vol. 11, no. 1
pp. 2093 – 2101

Abstract

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The replication and pathogenicity of SARS-CoV-2 Omicron BA.2 are comparable to that of BA.1 in experimental animal models. However, BA.2 has rapidly emerged to overtake BA.1 to become the predominant circulating SARS-CoV-2 variant worldwide. Here, we compared the replication fitness of BA.1 and BA.2 in cell culture and in the Syrian hamster model of COVID-19. Using a reverse genetics approach, we found that the BA.1-specific spike mutation G496S compromises its replication fitness, which may contribute to BA.1 being outcompeted by BA.2 in the real world. Additionally, the BA.1-unique G496S substitution confers differentiated sensitivity to therapeutic monoclonal antibodies, which partially recapitulates the immunoevasive phenotype of BA.1 and BA.2. In summary, our study identified G496S as an important determinant during the evolutionary trajectory of SARS-CoV-2.

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