Antigenicity assessment of SARS-CoV-2 saltation variant BA.2.87.1

ABSTRACT

The recent emergence of a SARS-CoV-2 saltation variant, BA.2.87.1, which features 65 spike mutations relative to BA.2, has attracted worldwide attention. In this study, we elucidate the antigenic characteristics and immune evasion capability of BA.2.87.1. Our findings reveal that BA.2.87.1 is more susceptible to XBB-induced humoral immunity compared to JN.1. Notably, BA.2.87.1 lacks critical escaping mutations in the receptor binding domain (RBD) thus allowing various classes of neutralizing antibodies (NAbs) that were escaped by XBB or BA.2.86 subvariants to neutralize BA.2.87.1, although the deletions in the N-terminal domain (NTD), specifically 15-23del and 136-146del, compensate for the resistance to humoral immunity. Interestingly, several neutralizing antibody drugs have been found to restore their efficacy against BA.2.87.1, including SA58, REGN-10933 and COV2-2196. Hence, our results suggest that BA.2.87.1 may not become widespread until it acquires multiple RBD mutations to achieve sufficient immune evasion comparable to that of JN.1.

KEYWORDS:

• SARS-CoV-2
• neutralizing antibodies
• humoral immunity
• immune escape
• saltation variant

Acknowledgments

We extend our gratitude to scientists in the community for their persistent monitoring of SARS-CoV-2 variants and valuable discussion. We thank all volunteers who contributed blood samples for this research.

Disclosure statement

Y.C. is the inventor of the provisional patent applications for BD series antibodies, which includes BD55-5514 (SA55), BD55-5840 (SA58) and BD55-1205. Y.C. is the founder of Singlomics Biopharmaceuticals. Other authors declare no competing interests.

Additional information

Funding

This work was supported by the Ministry of Science and Technology of China (2023YFC3043200), Changping Laboratory (2021A0201; 2021D0102) and the National Natural Science Foundation of China (32222030, 2023011477).