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Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies

The SARS-CoV-2 B.1.1.529 variant (Omicron) contains 15 mutations on the receptor-binding domain (RBD). How Omicron would evade RBD neutralizing antibodies (NAbs) requires immediate investigation.

In this article the authors used high-throughput yeast display screening to determine the RBD escaping mutation profiles for 247 human anti-RBD NAbs and showed that the NAbs could be unsupervised clustered into six epitope groups (A-F), which is highly concordant with knowledge-based structural classifications. Strikingly, various single mutations of Omicron could impair Nabs of different epitope groups. Specifically, NAbs in Group A-D, whose epitope overlap with ACE2-binding motif, are largely escaped by K417N, G446S, E484A, and Q493R. Group E (S309 site) and F (CR3022 site) NAbs, which often exhibit broad sarbecovirus neutralizing activity, are less affected by Omicron, but still, a subset of NAbs are escaped by G339D, N440K, and S371L. Furthermore, Omicron pseudovirus neutralization showed that single mutation tolerating NAbs could also be escaped due to multiple synergetic mutations on their epitopes. In total, over 85% of the tested Nabs are escaped by Omicron. Regarding NAb drugs, the neutralization potency of LY-CoV016/LY-CoV555, REGN10933/REGN10987, AZD1061/AZD8895, and BRII-196 were greatly reduced by Omicron, while VIR-7831 and DXP-604 still function at reduced efficacy. Together, these data suggest Omicron would cause significant humoral immune evasion, while NAbs targeting the sarbecovirus conserved region remain most effective. The authors concluded that their results offer instructions for developing NAb drugs and vaccines against Omicron and future variants.
Yunlong Cao , Jing Wang , Fanchong Jian , Tianhe Xiao , Weiliang Song , Ayijiang Yisimayi , Weijin Huang , Qianqian Li , Peng Wang , Ran An , Jing Wang , Yao Wang , Xiao Niu , Sijie Yang , Hui Liang , Haiyan Sun , Tao Li , Yuanling Yu , Qianqian Cui , Shuo Liu , Xiaodong Yang , Shuo Du , Zhiying Zhang , Xiaohua Hao , Fei Shao , Ronghua Jin , Xiangxi Wang , Junyu Xiao , Youchun Wang & Xiaoliang Sunney Xie. Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies. Nature.

doi: https://doi.org/10.1038/d41586-021-03796-6