The COVID-19 pandemic caused by SARS-CoV-2 virus is an ongoing global health burden.Severe cases of COVID-19 and the rare cases of COVID-19 vaccine-induced-thrombotic-thrombocytopenia(VITT)are both associated with thr...The COVID-19 pandemic caused by SARS-CoV-2 virus is an ongoing global health burden.Severe cases of COVID-19 and the rare cases of COVID-19 vaccine-induced-thrombotic-thrombocytopenia(VITT)are both associated with thrombosis and thrombocytopenia;however,the underlying mechanisms remain inadequately understood.Both infection and vaccination utilize the spike protein receptor-binding domain(RBD)of SARS-CoV-2.We found that intravenous injection of recombinant RBD caused significant platelet clearance in mice.Further investigation revealed the RBD could bind platelets,cause platelet activation,and potentiate platelet aggregation,which was exacerbated in the Delta and Kappa variants.The RBD–platelet interaction was partially dependent on theβ3 integrin as binding was significantly reduced inβ3−/−mice.Furthermore,RBD binding to human and mouse platelets was significantly reduced with relatedαIIbβ3 antagonists and mutation of the RGD(arginine-glycine-aspartate)integrin binding motif to RGE(arginine-glycine-glutamate).We developed anti-RBD polyclonal and several monoclonal antibodies(mAbs)and identified 4F2 and 4H12 for their potent dual inhibition of RBD-induced platelet activation,aggregation,and clearance in vivo,and SARS-CoV-2 infection and replication in Vero E6 cells.Our data show that the RBD can bind platelets partially thoughαIIbβ3 and induce platelet activation and clearance,which may contribute to thrombosis and thrombocytopenia observed in COVID-19 and VITT.Our newly developed mAbs 4F2 and 4H12 have potential not only for diagnosis of SARS-CoV-2 virus antigen but also importantly for therapy against COVID-19.展开更多
基金the Canadian Institutes of Health Research(CIHR)Foundation grant(389035)CCOA Therapeutics Inc.research fund to Dr.H.N.CIHR grant for COVID-19(OV3-170344,SBC-171482,and VS1-175560)to Dr.H.Z.D.T.M.,Z.C.,and DK are recipients of the Queen Elizabeth II(QE-II)Graduate Scholarship,Ontario,Canada.S.S.is a recipient of the Canadian Blood Services postdoctoral award.D.T.M.is a recipient of a Graduate Scholarship,Department of Physiology,University of Toronto.Z.C.is the recipient of the Canadian Blood Services Graduate Scholarship,Ontario,Canada.C.S.is a recipient of a postdoctoral Mitacs award,University of Toronto.Z.L.is a recipient of Mitacs Accelerate Postdoctoral Fellowship.LL is a recipient of a scholarship from the University of Chinese Academy of Sciences.X.W.is a recipient of Killam Research Fellowship from the Canadian Council for the Arts.D.K.is also the recipient of the St.Michael’s Hospital Research Training Centre Scholarship and the 2021-2022 Vanier Canada Graduate Scholarships(Vanier CGS),and V.P.is the recipient of the CGS awarded by the CIHR.
文摘The COVID-19 pandemic caused by SARS-CoV-2 virus is an ongoing global health burden.Severe cases of COVID-19 and the rare cases of COVID-19 vaccine-induced-thrombotic-thrombocytopenia(VITT)are both associated with thrombosis and thrombocytopenia;however,the underlying mechanisms remain inadequately understood.Both infection and vaccination utilize the spike protein receptor-binding domain(RBD)of SARS-CoV-2.We found that intravenous injection of recombinant RBD caused significant platelet clearance in mice.Further investigation revealed the RBD could bind platelets,cause platelet activation,and potentiate platelet aggregation,which was exacerbated in the Delta and Kappa variants.The RBD–platelet interaction was partially dependent on theβ3 integrin as binding was significantly reduced inβ3−/−mice.Furthermore,RBD binding to human and mouse platelets was significantly reduced with relatedαIIbβ3 antagonists and mutation of the RGD(arginine-glycine-aspartate)integrin binding motif to RGE(arginine-glycine-glutamate).We developed anti-RBD polyclonal and several monoclonal antibodies(mAbs)and identified 4F2 and 4H12 for their potent dual inhibition of RBD-induced platelet activation,aggregation,and clearance in vivo,and SARS-CoV-2 infection and replication in Vero E6 cells.Our data show that the RBD can bind platelets partially thoughαIIbβ3 and induce platelet activation and clearance,which may contribute to thrombosis and thrombocytopenia observed in COVID-19 and VITT.Our newly developed mAbs 4F2 and 4H12 have potential not only for diagnosis of SARS-CoV-2 virus antigen but also importantly for therapy against COVID-19.
