Structural definition of a neutralization epitope on the N-terminal domain of MERS-CoV spike glycoprotein

Haixia Zhou,Senyan Zhang,Yingzhu Chen,Baoying Huang,Kun Qin,Jun Lan,Xinquan Wang,Peihua Niu,Wenxu Jia,Wenjie Tan,Linqi Zhang,Shuyuan Zhang

doi:10.1038/s41467-019-10897-4

Abstract

Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). The epitopes and mechanisms of mAbs targeting non-RBD regions have not been well characterized yet. Here we report the monoclonal antibody 7D10 that binds to the N-terminal domain (NTD) of the spike glycoprotein and inhibits the cell entry of MERS-CoV with high potency. Structure determination and mutagenesis experiments reveal the epitope and critical residues on the NTD for 7D10 binding and neutralization. Further experiments indicate that the neutralization by 7D10 is not solely dependent on the inhibition of DPP4 binding, but also acts after viral cell attachment, inhibiting the pre-fusion to post-fusion conformational change of the spike. These properties give 7D10 a wide neutralization breadth and help explain its synergistic effects with several RBD-targeting antibodies.

Highlights

Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERSCoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4)
To generate MERS-CoV neutralizing Monoclonal antibodies (mAbs) with epitopes outside the RBD, mice were immunized with recombinant MERS-CoV S protein
We investigated the protective efficacy of 7D10-H against infection of pseudotyped MERS-CoV using R26-human dipeptidyl peptidase 4 (hDPP4) mice model with a human DPP4 inserted into the Rosa[26] locus by CRISPR/Cas[9], which could been productively infected by high-titer MERSCoV pseudovirus, with effects comparable to the authentic infection[28]

Summary

Introduction

Most neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERSCoV) target the receptor-binding domain (RBD) of the spike glycoprotein and block its binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). Further experiments indicate that the neutralization by 7D10 is not solely dependent on the inhibition of DPP4 binding, and acts after viral cell attachment, inhibiting the pre-fusion to post-fusion conformational change of the spike These properties give 7D10 a wide neutralization breadth and help explain its synergistic effects with several RBD-targeting antibodies. A series of RBD-targeting antibodies against MERS-CoV, which block the binding of the S trimer to the cellular receptor DPP4, have been reported and characterized[13,14,15,16,17,18,19,20,21,22] These antibodies exhibited high potency in inhibiting the infectivity of pseudotyped and live MERS-CoV in cells and animal models. All these results indicate that 7D10 is a very promising candidate for the future combined use of different antibodies in our battle against MERS-CoV

Methods

Results

Conclusion