Frontiers in Immunology (Jul 2022)

Reduced binding activity of vaccine serum to omicron receptor-binding domain

  • Mingzhi Li,
  • Shiqi Weng,
  • Quansheng Wang,
  • Zibing Yang,
  • Xiaoling Wang,
  • Xiaoling Wang,
  • Yanjun Yin,
  • Qiuxiang Zhou,
  • Lirong Zhang,
  • Feifei Tao,
  • Yihan Li,
  • Mengle Jia,
  • Lingdi Yang,
  • Xiu Xin,
  • Hanguang Li,
  • Lumei Kang,
  • Lumei Kang,
  • Yu Wang,
  • Ting Wang,
  • Sha Li,
  • Lingbao Kong

DOI
https://doi.org/10.3389/fimmu.2022.960195
Journal volume & issue
Vol. 13

Abstract

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Coronavirus disease 2019 (COVID-19) vaccination regimens contribute to limiting the spread of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2). However, the emergence and rapid transmission of the SARS-CoV-2 variant Omicron raise a concern about the efficacy of the current vaccination strategy. Here, we expressed monomeric and dimeric receptor-binding domains (RBDs) of the spike protein of prototype SARS-CoV-2 and Omicron variant in E. coli and investigated the reactivity of anti-sera from Chinese subjects immunized with SARS-CoV-2 vaccines to these recombinant RBDs. In 106 human blood samples collected from 91 participants from Jiangxi, China, 26 sera were identified to be positive for SARS-CoV-2 spike protein antibodies by lateral flow dipstick (LFD) assays, which were enriched in the ones collected from day 7 to 1 month post-boost (87.0%) compared to those harvested within 1 week post-boost (23.8%) (P < 0.0001). A higher positive ratio was observed in the child group (40.8%) than adults (13.6%) (P = 0.0073). ELISA results showed that the binding activity of anti-SARS-CoV-2 antibody-positive sera to Omicron RBDs dropped by 1.48- to 2.07-fold compared to its homogeneous recombinant RBDs. Thus, our data indicate that current SARS-CoV-2 vaccines provide restricted humoral protection against the Omicron variant.

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