scholarly journals pH-Induced Conformational Change of the Rotavirus VP4 Spike: Implications for Cell Entry and Antibody Neutralization

2005 ◽  
Vol 79 (13) ◽  
pp. 8572-8580 ◽  
Author(s):  
Joseph B. Pesavento ◽  
Sue E. Crawford ◽  
Ed Roberts ◽  
Mary K. Estes ◽  
B. V. Venkataram Prasad
Keyword(s):  
Monoclonal Antibody ◽  
Sialic Acid ◽  
Conformational Change ◽  
Cell Entry ◽  
Spike Protein ◽  
Cell Binding ◽  
Ph Changes ◽  
Multiple Receptors ◽  
Neutralizing Monoclonal Antibody ◽  
Dependent Cell

ABSTRACT The rotavirus spike protein, VP4, is a major determinant of infectivity and neutralization. Previously, we have shown that trypsin-enhanced infectivity of rotavirus involves a transformation of the VP4 spike from a flexible to a rigid bilobed structure. Here we show that at elevated pH the spike undergoes a drastic, irreversible conformational change and becomes stunted, with a pronounced trilobed appearance. These particles with altered spikes, at a normal pH of 7.5, despite the loss of infectivity and the ability to hemagglutinate, surprisingly exhibit sialic acid (SA)-independent cell binding in contrast to the SA-dependent cell binding exhibited by native virions. Remarkably, a neutralizing monoclonal antibody that remains bound to spikes throughout the pH changes (pH 7 to 11 and back to pH 7) completely prevents this conformational change, preserving the SA-dependent cell binding and hemagglutinating functions of the virion. A hypothesis that emerges from the present study is that high-pH treatment triggers a conformational change that mimics a post-SA-attachment step to expose an epitope recognized by a downstream receptor in the rotavirus cell entry process. This process involves sequential interactions with multiple receptors, and the mechanism by which the antibody neutralizes is by preventing this conformational change.

scholarly journals Molecular rationale for hantavirus neutralization by a reservoir host-derived monoclonal antibody

2020 ◽  
Author(s):  
Ilona Rissanen ◽  
Robert Stass ◽  
Stefanie A. Krumm ◽  
Jeffrey Seow ◽  
Ruben J.G. Hulswit ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Host Cell ◽  
Conformational Changes ◽  
Neutralizing Antibody ◽  
Crystallographic Analysis ◽  
Reservoir Host ◽  
Cell Entry ◽  
Cryo Electron Microscopy ◽  
Neutralizing Monoclonal Antibody ◽  
Host Cell Entry

AbstractThe intricate lattice of Gn and Gc glycoprotein spike complexes at the surface of hantaviruses facilitates host-cell entry and is the primary target of the neutralizing antibody-mediated immune response. Here, through study of a neutralizing monoclonal antibody (mAb 4G2) generated in a bank vole reservoir host following infection with Puumala virus (PUUV), we provide molecular-level insights into how antibody-mediated targeting of the hantaviral glycoprotein lattice effectively neutralizes the virus. Crystallographic analysis reveals that mAb 4G2 binds to a multi-domain site on Gc in the pre-fusion state, and that Fab binding is incompatible with the conformational changes of the Gc that are required for host cell entry. Cryo-electron microscopy of PUUV-like particles treated with Fab 4G2 demonstrates that the antibody binds to monomeric Gc at breaks in the Gn-Gc lattice, highlighting the immunological accessibility of Gc monomers on the mature hantavirus surface and the plastic nature of the higher-order lattice assembly. This work provides a structure-based blueprint for rationalizing antibody-mediated targeting of hantaviruses.

scholarly journals Disruption of Adaptive Immunity Enhances Disease in SARS-CoV-2 Infected Syrian Hamsters

2020 ◽  
Author(s):  
Rebecca L. Brocato ◽  
Lucia M. Principe ◽  
Robert K. Kim ◽  
Xiankun Zeng ◽  
Janice A. Williams ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Animal Models ◽  
Adaptive Immunity ◽  
Protective Efficacy ◽  
Severe Disease ◽  
Clinical Signs ◽  
Spike Protein ◽  
Syrian Hamsters ◽  
Viral Loads ◽  
Neutralizing Monoclonal Antibody

AbstractAnimal models recapitulating human COVID-19 disease, especially with severe disease, are urgently needed to understand pathogenesis and evaluate candidate vaccines and therapeutics. Here, we develop novel severe disease animal models for COVID-19 involving disruption of adaptive immunity in Syrian hamsters. Cyclophosphamide (CyP) immunosuppressed or RAG2 knockout (KO) hamsters were exposed to SARS-CoV-2 by the respiratory route. Both the CyP-treated and RAG2 KO hamsters developed clinical signs of disease that were more severe than in immunocompetent hamsters, notably weight loss, viral loads, and fatality (RAG2 KO only). Disease was prolonged in transiently immunosuppressed hamsters and uniformly lethal in RAG2 KO hamsters. We evaluated the protective efficacy of a neutralizing monoclonal antibody and found that pretreatment, even in immunosuppressed animals, limited infection. Our results suggest that functional B and/or T cells are not only important for the clearance of SARS-CoV-2, but also play an early role in protection from acute disease.One Sentence SummaryAn antibody targeting the spike protein of SARS-CoV-2 limits infection in immunosuppressed Syrian hamster models.

scholarly journals Sialic acid-dependent cell entry of human enterovirus D68

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Yue Liu ◽  
Ju Sheng ◽  
Jim Baggen ◽  
Geng Meng ◽  
Chuan Xiao ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Cell Entry ◽  
Human Enterovirus ◽  
Dependent Cell ◽  
Enterovirus D68

scholarly journals Proteolytic Activation of the Porcine Epidemic Diarrhea Coronavirus Spike Fusion Protein by Trypsin in Cell Culture

2014 ◽  
Vol 88 (14) ◽  
pp. 7952-7961 ◽  
Author(s):  
Oliver Wicht ◽  
Wentao Li ◽  
Lione Willems ◽  
Tom J. Meuleman ◽  
Richard W. Wubbolts ◽  
...  
Keyword(s):  
Cell Culture ◽  
Fusion Protein ◽  
Natural Infection ◽  
Animal Health ◽  
Proteolytic Processing ◽  
Cell Entry ◽  
Spike Protein ◽  
Proteolytic Activation ◽  
Dependent Cell ◽  
Porcine Epidemic Diarrhea

ABSTRACTIsolation of porcine epidemic diarrhea coronavirus (PEDV) from clinical material in cell culture requires supplementation of trypsin. This may relate to the confinement of PEDV natural infection to the protease-rich small intestine of pigs. Our study focused on the role of protease activity on infection by investigating the spike protein of a PEDV isolate (wtPEDV) using a reverse genetics system based on the trypsin-independent cell culture-adapted strain DR13 (caPEDV). We demonstrate that trypsin acts on the wtPEDV spike protein after receptor binding. We mapped the genetic determinant for trypsin-dependent cell entry to the N-terminal region of the fusion subunit of this class I fusion protein, revealing a conserved arginine just upstream of the putative fusion peptide as the potential cleavage site. Whereas coronaviruses are typically processed by endogenous proteases of the producer or target cell, PEDV S protein activation strictly required supplementation of a protease, enabling us to study mechanistic details of proteolytic processing.IMPORTANCERecurring PEDV epidemics constitute a serious animal health threat and an economic burden, particularly in Asia but, as of recently, also on the North-American subcontinent. Understanding the biology of PEDV is critical for combatting the infection. Here, we provide new insight into the protease-dependent cell entry of PEDV.

scholarly journals A novel neutralizing monoclonal antibody targeting the N-terminal domain of the MERS-CoV spike protein

2017 ◽  
Vol 6 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Yingzhu Chen ◽  
Shuai Lu ◽  
Hao Jia ◽  
Yao Deng ◽  
Jianfang Zhou ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Spike Protein ◽  
Terminal Domain ◽  
Neutralizing Monoclonal Antibody ◽  
Antibody Targeting

A Novel Neutralizing Monoclonal Antibody Against Cell-Binding Polypeptide of Ricin

Hybridoma ◽  
2005 ◽  
Vol 24 (5) ◽  
pp. 263-266 ◽  
Author(s):  
Jian-Wei Guo ◽  
Bei-Fen Shen ◽  
Jian-Nan Feng ◽  
Ying-Xun Sun ◽  
Ming Yu ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Cell Binding ◽  
Neutralizing Monoclonal Antibody

Neutralizing Monoclonal Antibody: New Member of Therapeutic Armamentarium Against COVID-19

2021 ◽  
Vol 11 (Number 2) ◽  
pp. 78-87
Author(s):  
Z H M Nazmul Alam ◽  
Ishrat Tahsin
Keyword(s):  
Monoclonal Antibody ◽  
Recombinant Proteins ◽  
Risk Groups ◽  
Target Population ◽  
Spike Protein ◽  
Passive Immunotherapy ◽  
Neutralizing Monoclonal Antibody ◽  
Optimal Deployment ◽  
Clinical Questions ◽  
New Treatments

Many targeted treatment methods have focused on SARS-CoV-2's spike protein, along with neutralizing monoclonal antibodies (mAbs), which are recombinant proteins, may be employed as a kind of passive immunotherapy to reduce pathogenicity. While vaccines are still the best way to prevent COVID-19 infection, mAbs are an effective treatment for those who have already been infected, as well as having the potential to prevent infection in those who have already been exposed to SARS-CoV-2, which can be especially beneficial to certain high-risk groups. Due to the limited initial availability of these new treatments, it is essential to consider their larger potential and create methods for their optimal deployment in clinical practice. The objectives of this review is to answer the most commonly asked clinical questions from HCPs and patients about the target population, dose, interactions with other medicines and vaccines, duration of immunity, and variants.

scholarly journals Identification of Potential Binding Sites of Sialic Acids on the RBD Domain of SARS-CoV-2 Spike Protein

2021 ◽  
Vol 9 ◽  
Author(s):  
Bingqian Li ◽  
Lin Wang ◽  
Huan Ge ◽  
Xianglei Zhang ◽  
Penxuan Ren ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Binding Sites ◽  
Sialic Acids ◽  
Host Cells ◽  
Spike Protein ◽  
Molecular Probe ◽  
Acetylneuraminic Acid ◽  
Mass Spectrum Analysis ◽  
Multiple Receptors ◽  
Potential Binding

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still an emergent pandemic for humans. The virus infection is achieved by penetrating its spike protein to host cells via binding with ACE2. Moreover, recent studies show that SARS-CoV-2 may have multiple receptors that need to be further revealed. SARS-CoV-2 shares similar sequences of the spike protein with the Middle East Respiratory Syndrome Coronavirus (MERS-CoV), which can invade host cells by binding to either DPP4 or sialic acids. Sialic acids can be linked to the terminal of glycoproteins and gangliosides are used as one of the receptors of many types of viruses. Therefore, it is very interesting to determine whether sialic acid is a potential receptor of SARS-CoV-2. To address this question, we took N-Acetylneuraminic acid (Neu5Ac), a type of predominant sialic acid found in human cells, as the molecular probe to computationally search the surface of the spike protein to locate the potential binding sites of Neu5Ac. SPR analysis and mass spectrum analysis confirmed the interaction between Neu5Ac and spike protein. This study shows that sialic acids can moderately interact with the spike protein of SARS-CoV-2 by binding between the two RBDs of the spike protein, indicating it could be a potential secondary or auxiliary receptor of SARS-CoV-2.

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