scholarly journals Structural basis for broad sarbecovirus neutralization by a human monoclonal antibody

2021 ◽  
Author(s):  
M. Alejandra Tortorici ◽  
Nadine Czudnochowski ◽  
Tyler N Starr ◽  
Roberta Marzi ◽  
Alexandra C. Walls ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Neutralizing Antibodies ◽  
Wide Spectrum ◽  
Human Monoclonal Antibody ◽  
Antigenic Site ◽  
Antigenic Drift ◽  
Structural Basis ◽  
Broadly Neutralizing Antibodies ◽  
Zoonotic Infections ◽  
Recent Emergence

The recent emergence of SARS-CoV-2 variants of concern (VOC) and the recurrent spillovers of coronaviruses in the human population highlight the need for broadly neutralizing antibodies that are not affected by the ongoing antigenic drift and that can prevent or treat future zoonotic infections. Here, we describe a human monoclonal antibody (mAb), designated S2X259, recognizing a highly conserved cryptic receptor-binding domain (RBD) epitope and cross-reacting with spikes from all sarbecovirus clades. S2X259 broadly neutralizes spike-mediated entry of SARS-CoV-2 including the B.1.1.7, B.1.351, P.1 and B.1.427/B.1.429 VOC, as well as a wide spectrum of human and zoonotic sarbecoviruses through inhibition of ACE2 binding to the RBD. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses a remarkably high barrier to the emergence of resistance mutants. We show that prophylactic administration of S2X259 protects Syrian hamsters against challenges with the prototypic SARS-CoV-2 and the B.1.351 variant, suggesting this mAb is a promising candidate for the prevention and treatment of emergent VOC and zoonotic infections. Our data unveil a key antigenic site targeted by broadly-neutralizing antibodies and will guide the design of pan-sarbecovirus vaccines.

scholarly journals Structural basis of a potent human monoclonal antibody against Zika virus targeting a quaternary epitope

2019 ◽  
Vol 116 (5) ◽  
pp. 1591-1596 ◽  
Author(s):  
Feng Long ◽  
Michael Doyle ◽  
Estefania Fernandez ◽  
Andrew S. Miller ◽  
Thomas Klose ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Zika Virus ◽  
Neutralizing Antibodies ◽  
Human Monoclonal Antibody ◽  
Structural Basis ◽  
E Proteins ◽  
Fab Fragment ◽  
Cryo Electron Microscopy ◽  
E Protein ◽  
Mouse Model Of Infection

Zika virus (ZIKV) is a major human pathogen and member of the Flavivirus genus in the Flaviviridae family. In contrast to most other insect-transmitted flaviviruses, ZIKV also can be transmitted sexually and from mother to fetus in humans. During recent outbreaks, ZIKV infections have been linked to microcephaly, congenital disease, and Guillain-Barré syndrome. Neutralizing antibodies have potential as therapeutic agents. We report here a 4-Å-resolution cryo-electron microscopy structure of the ZIKV virion in complex with Fab fragments of the potently neutralizing human monoclonal antibody ZIKV-195. The footprint of the ZIKV-195 Fab fragment expands across two adjacent envelope (E) protein protomers. ZIKV neutralization by this antibody is presumably accomplished by cross-linking the E proteins, which likely prevents formation of E protein trimers required for fusion of the viral and cellular membranes. A single dose of ZIKV-195 administered 5 days after virus inoculation showed marked protection against lethality in a stringent mouse model of infection.

scholarly journals Immunogenetic and structural analysis of a class of HCV broadly neutralizing antibodies and their precursors

2018 ◽  
Vol 115 (29) ◽  
pp. 7569-7574 ◽  
Author(s):  
Fernando Aleman ◽  
Netanel Tzarum ◽  
Leopold Kong ◽  
Kenna Nagy ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Structural Analysis ◽  
Neutralizing Antibodies ◽  
Antigenic Site ◽  
The Other ◽  
Maturation Process ◽  
Broadly Neutralizing Antibodies ◽  
Vaccine Candidates ◽  
Rational Vaccine Design ◽  
Hairpin Conformation

Elicitation of broadly neutralizing antibodies (bnAbs) is a leading strategy in rational vaccine design against antigenically diverse pathogens. Here, we studied a panel of monoclonal antibodies (mAbs) from mice immunized with the hepatitis C virus (HCV) envelope glycoproteins E1E2. Six of the mAbs recognize the conserved E2 antigenic site 412–423 (AS412) and cross-neutralize diverse HCV genotypes. Immunogenetic and structural analysis revealed that the antibodies originated from two different germline (GL) precursors and bind AS412 in a β-hairpin conformation. Intriguingly, the anti-HCV activity of one antibody lineage is associated with maturation of the light chain (LC), whereas the other lineage is dependent on heavy-chain (HC) maturation. Crystal structures of GL precursors of the LC-dependent lineage in complex with AS412 offer critical insights into the maturation process of bnAbs to HCV, providing a scientific foundation for utilizing the mouse model to study AS412-targeting vaccine candidates.

scholarly journals Isolation of a human monoclonal antibody specific for the receptor binding domain of SARS-CoV-2 using a competitive phage biopanning strategy

2020 ◽  
Vol 3 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Xin Zeng ◽  
Lingfang Li ◽  
Jing Lin ◽  
Xinlei Li ◽  
Bin Liu ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Magnetic Beads ◽  
Human Monoclonal Antibody ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Antibody Library ◽  
Synthetic Antibody ◽  
Blocking Antibodies

Abstract The infection of the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused more than 200 000 deaths, but no vaccine or therapeutic monoclonal antibody is currently available. SARS-CoV-2 relies on its spike protein, in particular the receptor-binding domain (RBD), to bind human cell receptor angiotensin-converting enzyme 2 (ACE2) for viral entry, and thus targeting RBD holds the promise for preventing SARS-CoV-2 infection. In this work, a competitive biopanning strategy of a phage display antibody library was applied to screen blocking antibodies against RBD. High-affinity antibodies were enriched after the first round using a standard panning process in which RBD-His was immobilized as a bait. At the next two rounds, immobilized ACE2-Fc and free RBD-His were mixed with the enriched phage antibodies. Antibodies binding to RBD at epitopes different from ACE2-binding site were captured by the immobilized ACE2-Fc, forming a “sandwich” complex. Only antibodies competed with ACE2 can bind to the free RBD-His in the supernatant and be subsequently separated by the nickel-nitrilotriacetic acid magnetic beads. rRBD-15 from the competitive biopanning of our synthetic antibody library, Lib AB1, was produced as the full-length IgG1 format. It was proved to competitively block the binding of RBD to ACE2 and potently inhibit SARS-CoV-2 pseudovirus infection with IC50 values of 12 nM. Nevertheless, rRBD-16 from the standard biopanning can only bind to RBD in vitro, but not have the blocking or neutralization activity. Our strategy can efficiently isolate the blocking antibodies of RBD, and it would speed up the discovery of neutralizing antibodies against SARS-CoV-2.

scholarly journals A novel antigenic site spanning domains I and III of the Zika virus envelope glycoprotein is the target of strongly neutralizing human monoclonal antibodies

2020 ◽  
Author(s):  
Stephen Graham ◽  
Huy A. Tu ◽  
Benjamin D. McElvany ◽  
Nancy R. Graham ◽  
Ariadna Grinyo ◽  
...  
Keyword(s):  
Zika Virus ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Severe Disease ◽  
Human Monoclonal Antibody ◽  
Antigenic Site ◽  
Viral Envelope ◽  
Virus Envelope ◽  
Human Antibodies

AbstractZika virus (ZIKV), a mosquito-transmitted flavivirus, caused a large epidemic in Latin America between 2015 and 2017. Effective ZIKV vaccines and treatments are urgently needed to prevent future epidemics and severe disease sequelae. People infected with ZIKV develop strongly neutralizing antibodies linked to viral clearance and durable protective immunity. To understand mechanisms of protective immunity and to support the development of ZIKV vaccines, here we characterize the properties of a strongly neutralizing antibody, B11F, isolated from a recovered ZIKV patient. Our results indicate that B11F targets a complex epitope on the virus that spans domains I and III of the envelope glycoprotein. While previous studies point to quaternary epitopes centered on domain II of ZIKV E glycoprotein as targets of strongly neutralizing and protective human antibodies, we uncover a new site spanning domain I and III as a target of strongly neutralizing human antibodies.ImportancePeople infected with Zika virus develop durable neutralizing antibodies that prevent repeat infections. In the current study, we characterize a ZIKV-neutralizing human monoclonal antibody isolated from a patient after recovery. Our studies establish a novel site on the viral envelope targeted by human neutralizing antibodies. Our results are relevant to understanding how antibodies block infection and for guiding the design and evaluation of candidate vaccines.

scholarly journals Structural Basis for Accommodation of Emerging B.1.351 and B.1.1.7 Variants by Two Potent SARS-CoV-2 Neutralizing Antibodies

2021 ◽  
Author(s):  
Gabriele Cerutti ◽  
Micah Rapp ◽  
Yicheng Guo ◽  
Fabiana Bahna ◽  
Jude Bimela ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Structural Basis ◽  
Wild Type Virus ◽  
Receptor Binding Domain ◽  
Type Virus ◽  
Wild Type ◽  
Distinct Mechanism ◽  
The Uk

SummaryEmerging SARS-CoV-2 strains, B.1.1.7 and B.1.351, from the UK and South Africa, respectively show decreased neutralization by monoclonal antibodies and convalescent or vaccinee sera raised against the original wild-type virus, and are thus of clinical concern. However, the neutralization potency of two antibodies, 1-57 and 2-7, which target the receptor-binding domain (RBD) of spike, was unaffected by these emerging strains. Here, we report cryo-EM structures of 1-57 and 2-7 in complex with spike, revealing each of these antibodies to utilize a distinct mechanism to bypass or accommodate RBD mutations. Notably, each antibody represented a response with recognition distinct from those of frequent antibody classes. Moreover, many epitope residues recognized by 1-57 and 2-7 were outside hotspots of evolutionary pressure for both ACE2 binding and neutralizing antibody escape. We suggest the therapeutic use of antibodies like 1-57 and 2-7, which target less prevalent epitopes, could ameliorate issues of monoclonal antibody escape.

scholarly journals Post-exposure protection of SARS-CoV-2 lethal infected K18-hACE2 transgenic mice by neutralizing human monoclonal antibody

2020 ◽  
Author(s):  
Ronit Rosenfeld ◽  
Tal Noy-Porat ◽  
Adva Mechaly ◽  
Efi Makdasi ◽  
Yinon Levy ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Transgenic Mice ◽  
Neutralizing Antibodies ◽  
Global Economy ◽  
Human Monoclonal Antibody ◽  
Human Monoclonal Antibodies ◽  
Mortality And Morbidity ◽  
Life Saving ◽  
Therapeutic Value

AbstractCoronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits high levels of mortality and morbidity and has dramatic consequences on human live, sociality and global economy. Neutralizing antibodies constitute a highly promising approach for treating and preventing infection by this novel pathogen. In the present study, we characterized and further evaluated the recently identified human monoclonal MD65 antibody for its ability to provide protection against a lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice. 75% of the untreated mice succumbed 6-9 days post-infection while administration of the MD65 antibody as late as 3 days after exposure, rescued all infected animals. The data unprecedentedly demonstrate, the therapeutic value of human monoclonal antibodies as a life-saving treatment of severe COVID-19 infection.

scholarly journals Antibody Pressure by a Human Monoclonal Antibody Targeting the 2009 Pandemic H1N1 Virus Hemagglutinin Drives the Emergence of a Virus with Increased Virulence in Mice

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Christopher D. O’Donnell ◽  
Leatrice Vogel ◽  
Amber Wright ◽  
Suman R. Das ◽  
Jens Wrammert ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Receptor Binding ◽  
H1n1 Virus ◽  
Human Monoclonal Antibody ◽  
Antigenic Drift ◽  
Pandemic H1n1 ◽  
Binding Properties ◽  
Immune Pressure ◽  
Escape Mutants

ABSTRACTIn 2009, a novel H1N1 influenza A virus (2009 pH1N1) emerged and caused a pandemic. A human monoclonal antibody (hMAb; EM4C04), highly specific for the 2009 pH1N1 virus hemagglutinin (HA), was isolated from a severely ill 2009 pH1N1 virus-infected patient. We postulated that under immune pressure with EM4C04, the 2009 pH1N1 virus would undergo antigenic drift and mutate at sites that would identify the antibody binding site. To do so, we infected MDCK cells in the presence of EM4C04 and generated 11 escape mutants, displaying 7 distinct amino acid substitutions in the HA. Six substitutions greatly reduced MAb binding (K123N, D131E, K133T, G134S, K157N, and G158E). Residues 131, 133, and 134 are contiguous with residues 157 and 158 in the globular domain structure and contribute to a novel pH1N1 antibody epitope. One mutation near the receptor binding site, S186P, increased the binding affinity of the HA to the receptor. 186P and 131E are present in the highly virulent 1918 virus HA and were recently identified as virulence determinants in a mouse-passaged pH1N1 virus. We found that pH1N1 escape variants expressing these substitutions enhanced replication and lethality in mice compared to wild-type 2009 pH1N1 virus. The increased virulence of these viruses was associated with an increased affinity for α2,3 sialic acid receptors. Our study demonstrates that antibody pressure by an hMAb targeting a novel epitope in the Sa region of 2009 pH1N1 HA is able to inadvertently drive the development of a more virulent virus with altered receptor binding properties. This broadens our understanding of antigenic drift.IMPORTANCEInfluenza viruses accumulate amino acid substitutions to evade the antibody response in a process known as antigenic drift, making it necessary to vaccinate against influenza annually. Mapping human monoclonal antibody (hMAb) epitopes is a necessary step towards understanding antigenic drift in humans. We defined the specificity of an hMAb that specifically targeted the 2009 pH1N1 virus and describe a novel epitope. In addition, we identified a previously unappreciated potential for antibody escape to enhance the pathogenicity of a virus. The escape mutation that we identified within vitroimmune pressure was independently reported by other investigators usingin vivoselection in nonimmune mice. Althoughin vitrogeneration of escape mutants is unlikely to recapitulate antigenic drift in its entirety, the data demonstrate that pressure by a human monoclonal antibody targeting a novel epitope in the hemagglutinin of the 2009 pandemic H1N1 virus can inadvertently drive the development of escape mutants, of which a subset have increased virulence and altered receptor binding properties.

scholarly journals Structural basis for the neutralization of MERS-CoV by a human monoclonal antibody MERS-27

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Xiaojuan Yu ◽  
Senyan Zhang ◽  
Liwei Jiang ◽  
Ye Cui ◽  
Dongxia Li ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Monoclonal Antibody ◽  
Structural Basis

scholarly journals Functional Transplant of a Dengue Virus Serotype 3 (DENV3)-Specific Human Monoclonal Antibody Epitope into DENV1

2016 ◽  
Vol 90 (10) ◽  
pp. 5090-5097 ◽  
Author(s):  
William B. Messer ◽  
Boyd L. Yount ◽  
Scott R. Royal ◽  
Ruklanthi de Alwis ◽  
Douglas G. Widman ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Human Monoclonal Antibody ◽  
Viral Envelope ◽  
Severe Dengue ◽  
Denv Serotypes ◽  
The Core ◽  
Antibody Epitope ◽  
Virus Serotype

ABSTRACTThe four dengue virus (DENV) serotypes, DENV1 through 4, are endemic throughout tropical and subtropical regions of the world. While first infection confers long-term protective immunity against viruses of the infecting serotype, a second infection with virus of a different serotype carries a greater risk of severe dengue disease, including dengue hemorrhagic fever and dengue shock syndrome. Recent studies demonstrate that humans exposed to DENV infections develop neutralizing antibodies that bind to quaternary epitopes formed by the viral envelope (E) protein dimers or higher-order assemblies required for the formation of the icosahedral viral envelope. Here we show that the quaternary epitope target of the human DENV3-specific neutralizing monoclonal antibody (MAb) 5J7 can be partially transplanted into a DENV1 strain by changing the core residues of the epitope contained within a single monomeric E molecule. MAb 5J7 neutralized the recombinant DENV1/3 strain in cell culture and was protective in a mouse model of infection with the DENV1/3 strain. However, the 5J7 epitope was only partially recreated by transplantation of the core residues because MAb 5J7 bound and neutralized wild-type (WT) DENV3 better than the DENV1/3 recombinant. Our studies demonstrate that it is possible to transplant a large number of discontinuous residues between DENV serotypes and partially recreate a complex antibody epitope, while retaining virus viability. Further refinement of this approach may lead to new tools for measuring epitope-specific antibody responses and new vaccine platforms.IMPORTANCEDengue virus is the most important mosquito-borne pathogen of humans worldwide, with approximately one-half the world's population living in regions where dengue is endemic. Dengue immunity following infection is robust and thought to be conferred by antibodies raised against the infecting virus. However, the specific viral components that these antibodies recognize and how they neutralize the virus have been incompletely described. Here we map a region on dengue virus serotype 3 recognized by the human neutralizing antibody 5J7 and then test the functional significance of this region by transplanting it into a serotype 1 virus. Our studies demonstrate a region on dengue virus necessary for 5J7 binding and neutralization. Our work also demonstrates the technical feasibility of engineering dengue viruses to display targets of protective antibodies. This technology can be used to develop new dengue vaccines and diagnostic assays.

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