scholarly journals Broad ultra-potent neutralization of SARS-CoV-2 variants by monoclonal antibodies specific to the tip of RBD

2021 ◽  
Author(s):  
Hang Ma ◽  
Yingying Guo ◽  
Haoneng Tang ◽  
Chien-Te Tseng ◽  
Lei Wang ◽  
...  
Keyword(s):  
Hydrophobic Effect ◽  
Receptor Binding Domain ◽  
Contact Interface ◽  
Block Interaction ◽  
Cryo Electron Microscopy ◽  
Binding Epitope ◽  
Clinical Illness ◽  
Animal Safety ◽  
Potent Neutralization

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) continue to wreak havoc across the globe. Higher transmissibility and immunologic resistance of VOCs bring unprecedented challenges to epidemic extinguishment. Here we describe a monoclonal antibody, 2G1, that neutralizes all current VOCs and has surprising tolerance to mutations adjacent to or within its interaction epitope. Cryo-electron microscopy structure showed that 2G1 bound to the tip of receptor binding domain (RBD) of spike protein with small contact interface but strong hydrophobic effect, which resulted in nanomolar to sub-nanomolar affinities to spike proteins. The epitope of 2G1 on RBD partially overlaps with ACE2 interface, which gives 2G1 ability to block interaction between RBD and ACE2. The narrow binding epitope but high affinity bestow outstanding therapeutic efficacy upon 2G1 that neutralized VOCs with sub-nanomolar IC50 in vitro. In SARS-CoV-2 and Beta- and Delta- variant-challenged transgenic mice and rhesus macaque models, 2G1 protected animals from clinical illness and eliminated viral burden, without serious impact to animal safety. Mutagenesis experiments suggest that 2G1 could be potentially capable of dealing with emerging SARS-CoV-2 variants in future. This report characterized the therapeutic antibodies specific to the tip of spike against SARS-CoV-2 variants and highlights the potential clinical applications as well as for developing vaccine and cocktail therapy.

scholarly journals A human monoclonal antibody potently pan-neutralizes SARS-CoV-2 VOCs by targeting RBD invariant sites

2021 ◽  
Author(s):  
Xiaofei Wang ◽  
Ao Hu ◽  
Xiangyu Chen ◽  
Yixin Zhang ◽  
Fei Yu ◽  
...  
Keyword(s):  
Rational Design ◽  
Virus Disease ◽  
Human Monoclonal Antibody ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Cryo Electron Microscopy ◽  
Global Pandemic ◽  
Binding Epitope

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel corona virus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.

scholarly journals Potent Neutralizing Antibodies Directed to Multiple Epitopes on SARS-CoV-2 Spike

2020 ◽  
Author(s):  
Lihong Liu ◽  
Pengfei Wang ◽  
Manoj S. Nair ◽  
Jian Yu ◽  
Micah Rapp ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Neutralizing Antibodies ◽  
Global Economy ◽  
Epitope Mapping ◽  
Severe Disease ◽  
Clinical Development ◽  
Receptor Binding Domain ◽  
Cryo Electron Microscopy ◽  
Novel Coronavirus

AbstractThe SARS-CoV-2 pandemic rages on with devasting consequences on human lives and the global economy1,2. The discovery and development of virus-neutralizing monoclonal antibodies could be one approach to treat or prevent infection by this novel coronavirus. Here we report the isolation of 61 SARS-CoV-2-neutralizing monoclonal antibodies from 5 infected patients hospitalized with severe disease. Among these are 19 antibodies that potently neutralized the authentic SARS-CoV-2 in vitro, 9 of which exhibited exquisite potency, with 50% virus-inhibitory concentrations of 0.7 to 9 ng/mL. Epitope mapping showed this collection of 19 antibodies to be about equally divided between those directed to the receptor-binding domain (RBD) and those to the N-terminal domain (NTD), indicating that both of these regions at the top of the viral spike are immunogenic. In addition, two other powerful neutralizing antibodies recognized quaternary epitopes that are overlapping with the domains at the top of the spike. Cryo-electron microscopy reconstructions of one antibody targeting RBD, a second targeting NTD, and a third bridging two separate RBDs revealed recognition of the closed, “all RBD-down” conformation of the spike. Several of these monoclonal antibodies are promising candidates for clinical development as potential therapeutic and/or prophylactic agents against SARS-CoV-2.

scholarly journals The functions of SARS-CoV-2 neutralizing and infection-enhancing antibodies in vitro and in mice and nonhuman primates

2021 ◽  
Author(s):  
Dapeng Li ◽  
Robert J Edwards ◽  
Kartik Manne ◽  
David R. Martinez ◽  
Alexandra Schäfer ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Nonhuman Primates ◽  
Safety Concern ◽  
Lung Pathology ◽  
Receptor Binding Domain ◽  
Biologically Relevant ◽  
Cryo Electron Microscopy ◽  
History Of

SummarySARS-CoV-2 neutralizing antibodies (NAbs) protect against COVID-19, making them a focus of vaccine design. A safety concern regarding SARS-CoV-2 antibodies is whether they mediate disease enhancement. Here, we isolated potent NAbs against the receptor-binding domain (RBD) and the N-terminal domain (NTD) of SARS-CoV-2 spike protein from individuals with acute or convalescent SARS-CoV-2 or a history of SARS-CoV-1 infection. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific modes of antibody binding. Select RBD NAbs also demonstrated Fc receptor-γ (FcγR)-mediated enhancement of virus infection in vitro, while five non-neutralizing NTD antibodies mediated FcγR-independent in vitro infection enhancement. However, both in vitro neutralizing and infection-enhancing RBD or infection-enhancing NTD antibodies protected from SARS-CoV-2 challenge in non-human primates and mice. One of 30 monkeys infused with enhancing antibodies had lung pathology and bronchoalveolar lavage cytokine evidence suggestive of enhanced disease. Thus, these in vitro assessments of enhanced antibody-mediated infection do not necessarily indicate biologically relevant in vivo infection enhancement.

scholarly journals Structure-guided antibody cocktail for prevention and treatment of COVID-19

2021 ◽  
Vol 17 (10) ◽  
pp. e1009704
Author(s):  
Shih-Chieh Su ◽  
Tzu-Jing Yang ◽  
Pei-Yu Yu ◽  
Kang-Hao Liang ◽  
Wan-Yu Chen ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Spike Protein ◽  
Great Promise ◽  
Cryo Electron Microscopy ◽  
Control Disease ◽  
Antibody Cocktail ◽  
Potent Neutralization

Development of effective therapeutics for mitigating the COVID-19 pandemic is a pressing global need. Neutralizing antibodies are known to be effective antivirals, as they can be rapidly deployed to prevent disease progression and can accelerate patient recovery without the need for fully developed host immunity. Here, we report the generation and characterization of a series of chimeric antibodies against the receptor-binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Some of these antibodies exhibit exceptionally potent neutralization activities in vitro and in vivo, and the most potent of our antibodies target three distinct non-overlapping epitopes within the RBD. Cryo-electron microscopy analyses of two highly potent antibodies in complex with the SARS-CoV-2 spike protein suggested they may be particularly useful when combined in a cocktail therapy. The efficacy of this antibody cocktail was confirmed in SARS-CoV-2-infected mouse and hamster models as prophylactic and post-infection treatments. With the emergence of more contagious variants of SARS-CoV-2, cocktail antibody therapies hold great promise to control disease and prevent drug resistance.

scholarly journals Potent neutralization of 2019 novel coronavirus by recombinant ACE2-Ig

2020 ◽  
Author(s):  
Changhai Lei ◽  
Wenyan Fu ◽  
Kewen Qian ◽  
Tian Li ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Fusion Proteins ◽  
Antiviral Treatment ◽  
Cross Reactivity ◽  
Cell Entry ◽  
Receptor Binding Domain ◽  
Potential Applications ◽  
Novel Coronavirus ◽  
Entry Receptor ◽  
Potent Neutralization

Abstract2019-nCoV, which is a novel coronavirus emerged in Wuhan, China, at the end of 2019, has caused at least infected 11,844 as of Feb 1, 2020. However, there is no specific antiviral treatment or vaccine currently. Very recently report had suggested that novel CoV would use the same cell entry receptor, ACE2, as the SARS-CoV. In this report, we generated a novel recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. An ACE2 mutant with low catalytic activity was also used in the study. The fusion proteins were then characterized. Both fusion proteins has high affinity binding to the receptor-binding domain (RBD) of SARS-CoV and 2019-nCoV and exerted desired pharmacological properties. Moreover, fusion proteins potently neutralized SARS-CoV and 2019-nCoV in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they could have potential applications for diagnosis, prophylaxis, and treatment of 2019-nCoV.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

scholarly journals Prospective mapping of viral mutations that escape antibodies used to treat COVID-19

Science ◽  
2021 ◽  
Vol 371 (6531) ◽  
pp. 850-854 ◽  
Author(s):  
Tyler N. Starr ◽  
Allison J. Greaney ◽  
Amin Addetia ◽  
William W. Hannon ◽  
Manish C. Choudhary ◽  
...  
Keyword(s):  
Amino Acid ◽  
Infected Patient ◽  
Viral Escape ◽  
Single Amino Acid ◽  
Receptor Binding Domain ◽  
Amino Acid Mutation ◽  
The Individual ◽  
Viral Surveillance ◽  
Single Amino Acid Mutation

Antibodies are a potential therapy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the risk of the virus evolving to escape them remains unclear. Here we map how all mutations to the receptor binding domain (RBD) of SARS-CoV-2 affect binding by the antibodies in the REGN-COV2 cocktail and the antibody LY-CoV016. These complete maps uncover a single amino acid mutation that fully escapes the REGN-COV2 cocktail, which consists of two antibodies, REGN10933 and REGN10987, targeting distinct structural epitopes. The maps also identify viral mutations that are selected in a persistently infected patient treated with REGN-COV2 and during in vitro viral escape selections. Finally, the maps reveal that mutations escaping the individual antibodies are already present in circulating SARS-CoV-2 strains. These complete escape maps enable interpretation of the consequences of mutations observed during viral surveillance.

scholarly journals Laboratory Safety, Biosecurity, and Responsible Animal Use

ILAR Journal ◽  
2019 ◽  
Author(s):  
Jessica McCormick-Ell ◽  
Nancy Connell
Keyword(s):  
Health And Safety ◽  
Chemical Exposure ◽  
Mitigation Strategies ◽  
Worker Safety ◽  
Environmental Health And Safety ◽  
Safety Research ◽  
Education Levels ◽  
Animal Safety ◽  
Animal Care

AbstractResearch with animals presents a wide array of hazards, some of which overlap those in the in vitro research laboratory. The challenge for environmental health and safety professionals when making their recommendations and performing the risk assessment is to balance worker safety with animal safety/welfare. The care and husbandry of animals require procedures and tasks that create aerosols and involve metabolized chemicals and a variety of physical hazards that must be assessed in addition to the research related risks, all while balancing the biosecurity of the facility and NIH animal care requirements. Detailed communication between health and safety, research, and animal care teams is essential to understand how to mitigate the risks that are present and if modifications need to be made as the experiments and processes progress and change over time. Additionally, the backgrounds and education levels of the persons involved in animal research and husbandry can be quite broad; the training programs created need to reflect this. Active learning and hands-on training are extremely beneficial for all staff involved in this field. Certain areas of research, such as infectious disease research in high- and maximum-containment (biosafety level 3 and 4) facilities, present challenges that are not seen in lower containment or chemical exposure experiments. This paper reviews potential hazards and mitigation strategies and discusses unique challenges for safety at all biosafety levels.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

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