Immune evasion is a pivotal force shaping the evolution of viruses.Nonetheless,the extent to which virus evolution varies among populations with diverse immune backgrounds remains an unsolved mystery.Prior to the widespread SARS-CoV-2 infections in December 2022 and January 2023,the Chinese population possessed a markedly distinct(less potent)immune background due to its low infection rate,compared to countries experiencing multiple infection waves,presenting an unprecedented opportunity to investigate how the virus has evolved under different immune contexts.We compared the mutation spectrum and functional potential of the newly derived mutations that occurred in BA.5.2.48,BF.7.14 and BA.5.2.49-variants prevalent in China-with their counterparts in other countries.We found that the emerging mutations in the receptor-binding-domain region in these lineages were more widely dispersed and evenly distributed across different epitopes.These mutations led to a higher angiotensin-converting enzyme 2(ACE2)binding affinity and reduced potential for immune evasion compared to their counterparts in other countries.These findings suggest a milder immune pressure and less evident immune imprinting within the Chinese population.Despite the emergence of numerous immune-evading variants in China,none of them outcompeted the original strain until the arrival of the XBB variant,which had stronger immune evasion and subsequently outcompeted all circulating variants.Our findings demonstrated that the continuously changing immune background led to varying evolutionary pressures on SARS-CoV-2.Thus,in addition to viral genome surveillance,immune background surveillance is also imperative for predicting forthcoming mutations and understanding how these variants spread in the population.
SARS-CoV-2evolutionmutationpopulation immunity
Wentai Ma、Haoyi Fu、Fanchong Jian、Yunlong Cao、Mingkun Li
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Beijing Institute of Genomics,Chinese Academy of Sciences,and China National Center for Bioinformation,Beijing 100101,China
University of Chinese Academy of Sciences,Beijing 100049,China
Key Collaborative Research Program of the Alliance of International Science OrganizationsNational Natural Science Foundation of ChinaStrategic Priority Research Program of the Chinese Academy of Sciences
NETL
NSTL
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