SARS-CoV-2 variants with adaptive mutations have continued to emerge,causing fresh waves of infection even amongst vaccinated population.The development of broad-spectrum antivirals is thus urgently needed.We previously developed two hetero-bivalent nanobodies(Nbs),aRBD-2-5 and aRBD-2-7,with potent neutralization activity against the wild-type(WT)Wuhan isolated SARS-CoV-2,by fusing aRBD-2 with aRBD-5 and aRBD-7,respectively.Here,we resolved the crystal structures of these Nbs in complex with the receptor-binding domain(RBD)of the spike protein,and found that aRBD-2 contacts with highly-conserved RBD residues and retains binding to the RBD of the Alpha,Beta,Gamma,Delta,Delta plus,Kappa,Lambda,Omicron BA.1,and BA.2 variants.In contrast,aRBD-5 and aRBD-7 bind to less-conserved RBD epitopes non-overlapping with the epitope of aRBD-2,and do not show apparent binding to the RBD of some variants.However,when fused with aRBD-2,they effectively enhance the overall binding affinity.Consistently,aRBD-2-5-Fc and aRBD-2-7-Fc potently neutralized all of the tested authentic or pseudotyped viruses,including WT,Alpha,Beta,Gamma,Delta,and Omicron BA.1,BA.1.1 and BA.2.Furthermore,aRBD-2-5-Fc provided prophylactic protection against the WT and mouse-adapted SARS-CoV-2 in mice,and conferred protection against the Omicron BA.1 variant in hamsters prophylactically and therapeutically,indicating that aRBD-2-5-Fc could potentially benefit the prevention and treatment of COVID-19 caused by the emerging variants of concern.Our strategy provides new solutions in the development of broad-spectrum therapeutic antibodies for COVID-19.

Huan Ma;Xinghai Zhang;Peiyi Zheng;Peter H.Dube;Weihong Zeng;Shaohong Chen;Qingyu Cheng;Yunru Yang;Yan Wu;Junhui Zhou;Xiaowen Hu;Yan Xiang;Huajun Zhang;Sandra Chiu;Tengchuan Jin

Department of Pulmonary and Critical Care Medicine,The First Affiliated Hospital of USTC,Division of Life Sciences and Medicine,University of Science and Technology of China,Hefei,Anhui,China;State Key Laboratory of Virology,Wuhan Institute of Virology,Center for Biosafety Mega-Science,Chinese Academy of Sciences,Wuhan,Hubei,China;Laboratory of Structural Immunology,CAS Key Laboratory of Innate Immunity and Chronic Disease,Hefei National Laboratory for Physical Sciences at Microscale,Division of Life Sciences and Medicine,University of Science and Technology of China,Hefei,Anhui,China;Department of Microbiology,Immunology and Molecular Genetics,University of Texas Health Science Center at San Antonio,San Antonio,TX,USA;University of Chinese Academy of Sciences,Beijing,China;Institute of Health and Medicine,Hefei Comprehensive National Science Center,Hefei,Anhui,China

细胞研究（英文版）

[1]Huan Ma;Xinghai Zhang;Peiyi Zheng;Peter H.Dube;Weihong Zeng;Shaohong Chen;Qingyu Cheng;Yunru Yang;Yan Wu;Junhui Zhou;Xiaowen Hu;Yan Xiang;Huajun Zhang;Sandra Chiu;Tengchuan Jin-.Hetero-bivalent nanobodies provide broad-spectrum protection against SARS-CoV-2 variants of concern including Omicron)[J].细胞研究（英文版）,2022(09):831-842

Nbs,aRBD,pseudotyped,prophylactically

Hetero,bivalent,nanobodies,broad,spectrum,protection,against,SARS,CoV,variants,concern,including,Omicron,adaptive,mutations,have,continued,emerge,causing,fresh,waves,infection,amongst,vaccinated,population,development,antivirals,thus,urgently,needed,We,previously,developed,two,hetero,neutralization,activity,wild,WT,Wuhan,isolated,by,fusing,respectively,Here,resolved,crystal,structures,these,complex,receptor,binding,domain,spike,protein,found,that,contacts,highly,conserved,residues,retains,Alpha,Beta,Gamma,Delta,plus,Kappa,Lambda,BA,In,contrast,less,epitopes,overlapping,not,show,apparent,some,However,when,fused,they,effectively,enhance,overall,affinity,Consistently,Fc,potently,neutralized,tested,authentic,viruses,Furthermore,provided,mouse,adapted,mice,conferred,hamsters,therapeutically,indicating,could,potentially,benefit,prevention,treatment,caused,emerging,Our,strategy,provides,new,solutions,antibodies

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