Natural mutations in the receptor binding domain of spike glycoprotein determine the reactivity of cross-neutralization between palm civet coronavirus and severe acute respiratory syndrome coronavirus.
The severe acute respiratory syndrome (SARS) outbreak of 2002 and 2003 occurred as a result of zoonotic transmission. Coronavirus (CoV) found in naturally infected palm civet (civet-CoV) represents the closest genetic relative to SARS-CoV, but the degree and the determinants of cross-neutralization among these viruses remain to be investigated. Studies indicate that the receptor binding domain (RBD) of the SARS-CoV spike (S) glycoprotein contains major determinants for viral entry and neutralization. We aim to characterize the impact of natural mutations within the RBDs of civet-CoVs on viral entry and cross-neutralization. In this study, the S glycoprotein genes were recovered from naturally infected civets in central China (Hubei province), extending the geographic distribution of civet-CoV beyond the southeastern province of Guangdong. Moreover, pseudoviruses generated in our laboratory with four civet S genes, each with a distinct RBD, infected cells expressing human receptor angiotensin-converting enzyme 2, but with 90 to 95% less efficiency compared to that of SARS-CoV. These four civet S genes were also constructed as DNA vaccines to immunize mice. Immunized sera elicited against most civet S glycoproteins displayed potent neutralizing activities against autologous viruses but were much less efficient (50% inhibitory concentration, 20- to 40-fold) at neutralizing SARS-CoV and vice versa. Convalescence-phase sera from humans were similarly ineffective against the dominant civet pseudovirus. Our findings suggest that the design of SARS vaccine should consider not only preventing the reemergence of SARS-CoV but also providing cross-protection, thus interrupting zoonotic transmission of a group of genetically divergent civet CoVs of broad geographic origin.
Liu
Li
L
Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NY 10016, USA.
Fang
Qing
Q
Deng
Fei
F
Wang
Hanzhong
H
Yi
Christopher E
CE
Ba
Lei
L
Yu
Wenjie
W
Lin
Richard D
RD
Li
Taisheng
T
Hu
Zhihong
Z
Ho
David D
DD
Zhang
Linqi
L
Chen
Zhiwei
Z
D001483:Base Sequence; D002681:China; D016000:Cluster Analysis; D003429:Cross Reactions / Q000235:genetics* / Q000276:immunology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009500:Neutralization Tests; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics*; D017422:Sequence Analysis, DNA; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000378:metabolism
D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins