Neutralizing and protective human monoclonal antibodies recognizing the N-terminal domain of the SARS-CoV-2 spike protein

SummaryMost human monoclonal antibodies (mAbs) neutralizing SARS-CoV-2 recognize the spike (S) protein receptor-binding domain and block virus interactions with the cellular receptor angiotensin-converting enzyme 2. We describe a panel of human mAbs binding to diverse epitopes on the N-terminal domain (NTD) of S protein from SARS-CoV-2 convalescent donors and found a minority of these possessed neutralizing activity. Two mAbs (COV2-2676 and COV2-2489) inhibited infection of authentic SARS-CoV-2 and recombinant VSV/SARS-CoV-2 viruses. We mapped their binding epitopes by alanine-scanning mutagenesis and selection of functional SARS-CoV-2 S neutralization escape variants. Mechanistic studies showed that these antibodies neutralize in part by inhibiting a post-attachment step in the infection cycle. COV2-2676 and COV2-2489 offered protection either as prophylaxis or therapy, and Fc effector functions were required for optimal protection. Thus, natural infection induces a subset of potent NTD-specific mAbs that leverage neutralizing and Fc-mediated activities to protect against SARS-CoV-2 infection using multiple functional attributes.

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Identification of neutralizing human monoclonal antibodies from Italian Covid-19 convalescent patients

10.1101/2020.05.05.078154 ◽

2020 ◽

Cited By ~ 12

Author(s):

Emanuele Andreano ◽

Emanuele Nicastri ◽

Ida Paciello ◽

Piero Pileri ◽

Noemi Manganaro ◽

...

Keyword(s):

Monoclonal Antibodies ◽

B Lymphocytes ◽

Neutralizing Antibodies ◽

Memory B Cells ◽

Spike Protein ◽

Human Monoclonal Antibodies ◽

Natural Production ◽

Development Pipeline ◽

Approved Drugs

ABSTRACTIn the absence of approved drugs or vaccines, there is a pressing need to develop tools for therapy and prevention of Covid-19. Human monoclonal antibodies have very good probability of being safe and effective tools for therapy and prevention of SARS-CoV-2 infection and disease. Here we describe the screening of PBMCs from seven people who survived Covid-19 infection to isolate human monoclonal antibodies against SARS-CoV-2. Over 1,100 memory B cells were single-cell sorted using the stabilized prefusion form of the spike protein and incubated for two weeks to allow natural production of antibodies. Supernatants from each cell were tested by ELISA for spike protein binding, and positive antibodies were further tested for neutralization of spike binding to receptor(s) on Vero E6 cells and for virus neutralization in vitro. From the 1,167 memory B specific for SARS-CoV-2, we recovered 318 B lymphocytes expressing human monoclonals recognizing the spike protein and 74 of these were able to inhibit the binding of the spike protein to the receptor. Finally, 17 mAbs were able to neutralize the virus when assessed for neutralization in vitro. Lead candidates to progress into the drug development pipeline will be selected from the panel of neutralizing antibodies identified with the procedure described in this study.One Sentence SummaryNeutralizing human monoclonal antibodies isolated from Covid-19 convalescent patients for therapeutic and prophylactic interventions.

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A neutralizing human antibody binds to the N-terminal domain of the Spike protein of SARS-CoV-2

Science ◽

10.1126/science.abc6952 ◽

2020 ◽

Vol 369 (6504) ◽

pp. 650-655 ◽

Cited By ~ 166

Author(s):

Xiangyang Chi ◽

Renhong Yan ◽

Jun Zhang ◽

Guanying Zhang ◽

Yuanyuan Zhang ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Severe Acute Respiratory Syndrome ◽

Receptor Binding ◽

Binding Domain ◽

Spike Protein ◽

Human Antibody ◽

Receptor Binding Domain ◽

S Protein ◽

Terminal Domain ◽

Promising Target

Developing therapeutics against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the Spike (S) protein but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from 10 convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. One mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2 but does not bind the RBD. We defined the epitope of 4A8 as the N-terminal domain (NTD) of the S protein by determining with cryo–eletron microscopy its structure in complex with the S protein to an overall resolution of 3.1 angstroms and local resolution of 3.3 angstroms for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.

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A conserved immunogenic and vulnerable site on the coronavirus spike protein delineated by cross-reactive monoclonal antibodies

Nature Communications ◽

10.1038/s41467-021-21968-w ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Chunyan Wang ◽

Rien van Haperen ◽

Javier Gutiérrez-Álvarez ◽

Wentao Li ◽

Nisreen M. A. Okba ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Cross Reactivity ◽

Cell Entry ◽

Spike Protein ◽

Structural Studies ◽

Human Monoclonal Antibodies ◽

Human Coronavirus ◽

Helical Bundle ◽

Protective Antibodies ◽

Virion Surface

AbstractThe coronavirus spike glycoprotein, located on the virion surface, is the key mediator of cell entry and the focus for development of protective antibodies and vaccines. Structural studies show exposed sites on the spike trimer that might be targeted by antibodies with cross-species specificity. Here we isolated two human monoclonal antibodies from immunized humanized mice that display a remarkable cross-reactivity against distinct spike proteins of betacoronaviruses including SARS-CoV, SARS-CoV-2, MERS-CoV and the endemic human coronavirus HCoV-OC43. Both cross-reactive antibodies target the stem helix in the spike S2 fusion subunit which, in the prefusion conformation of trimeric spike, forms a surface exposed membrane-proximal helical bundle. Both antibodies block MERS-CoV infection in cells and provide protection to mice from lethal MERS-CoV challenge in prophylactic and/or therapeutic models. Our work highlights an immunogenic and vulnerable site on the betacoronavirus spike protein enabling elicitation of antibodies with unusual binding breadth.

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Cross-Neutralization of Emerging SARS-CoV-2 Variants of Concern by Antibodies Targeting Distinct Epitopes on Spike

mBio ◽

10.1128/mbio.02975-21 ◽

2021 ◽

Author(s):

Siriruk Changrob ◽

Yanbin Fu ◽

Jenna J. Guthmiller ◽

Peter J. Halfmann ◽

Lei Li ◽

...

Keyword(s):

Monoclonal Antibodies ◽

B Cells ◽

Memory B Cells ◽

Human Monoclonal Antibodies ◽

Terminal Domain ◽

Cross Neutralization ◽

Pandemic Wave

We describe the binding and neutralization properties of a new set of human monoclonal antibodies derived from memory B cells of 10 coronavirus disease 2019 (COVID-19) convalescent donors in the first pandemic wave of prototype SARS-CoV-2. There were 12 antibodies targeting distinct epitopes on spike, including two sites on the RBD and one on the N-terminal domain (NTD), that displayed cross-neutralization of VOCs, for which distinct antibody targets could neutralize discrete variants.

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In Silico Analyses on the Comparative Potential of Therapeutic Human Monoclonal Antibodies Against Newly Emerged SARS-CoV-2 Variants Bearing Mutant Spike Protein

Frontiers in Immunology ◽

10.3389/fimmu.2021.782506 ◽

2022 ◽

Vol 12 ◽

Author(s):

Nabarun Chandra Das ◽

Pritha Chakraborty ◽

Jagadeesh Bayry ◽

Suprabhat Mukherjee

Keyword(s):

Monoclonal Antibodies ◽

In Silico ◽

Spike Protein ◽

Economic Losses ◽

Chimeric Antibody ◽

Stable Complex ◽

Human Monoclonal Antibodies ◽

Chimeric Antibodies ◽

In Silico Analyses ◽

Potential Use

Since the start of the pandemic, SARS-CoV-2 has already infected more than 250 million people globally, with more than five million fatal cases and huge socio-economic losses. In addition to corticosteroids, and antiviral drugs like remdesivir, various immunotherapies including monoclonal antibodies (mAbs) to S protein of SARS-CoV-2 have been investigated to treat COVID-19 patients. These mAbs were initially developed against the wild-type SARS-CoV-2; however, emergence of variant forms of SARS-CoV-2 having mutations in the spike protein in several countries including India raised serious questions on the potential use of these mAbs against SARS-CoV-2 variants. In this study, using an in silico approach, we have examined the binding abilities of eight mAbs against several SARS-CoV-2 variants of Alpha (B.1.1.7) and Delta (B.1.617.2) lineages. The structure of the Fab region of each mAb was designed in silico and subjected to molecular docking against each mutant protein. mAbs were subjected to two levels of selection based on their binding energy, stability, and conformational flexibility. Our data reveal that tixagevimab, regdanvimab, and cilgavimab can efficiently neutralize most of the SARS-CoV-2 Alpha strains while tixagevimab, bamlanivimab, and sotrovimab can form a stable complex with the Delta variants. Based on these data, we have designed, by in silico, a chimeric antibody by conjugating the CDRH3 of regdanivimab with a sotrovimab framework to combat the variants that could potentially escape from the mAb-mediated neutralization. Our finding suggests that though currently available mAbs could be used to treat COVID-19 caused by the variants of SARS-CoV-2, better results could be expected with the chimeric antibodies.

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