scholarly journals A synthetic bispecific antibody capable of neutralizing SARS-CoV-2 Delta and Omicron

2022 ◽  
Author(s):  
Tom Z Yuan ◽  
Carolina Lucas ◽  
Valter S Monteiro ◽  
Akiko Iwasaki ◽  
Marisa L Yang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Bispecific Antibody ◽  
Immune Escape ◽  
Binding Domain ◽  
Bispecific Antibodies ◽  
Receptor Binding Domain ◽  
Promising Strategy

Bispecific antibodies have emerged as a promising strategy for curtailing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune escape. This brief report highlights RBT-0813 (also known as TB493-04), a synthetic, humanized, receptor-binding domain (RBD)-targeted bispecific antibody that retains picomolar affinity to the Spike (S) trimers of all major variants of concern and neutralizes both SARS-CoV-2 Delta and Omicron in vitro.

scholarly journals Efficacy of ancestral receptor-binding domain, S1 and trimeric spike protein vaccines against SARS-CoV-2 variants B.1.1.7, B.1.351, and B.1.617.1

2021 ◽  
Author(s):  
Yong Yang ◽  
Jinkai Zang ◽  
Shiqi Xu ◽  
Xueyang Zhang ◽  
Sule Yuan ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Immune Escape ◽  
Neutralizing Antibody ◽  
Prototype Strain ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Antibody Titers ◽  
Continued Use

The ongoing coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The current SARS-CoV-2 vaccines are based on spike (S) protein, S1 subunit, or receptor-binding domain (RBD) of prototype strain. Emergence of several novel SARS-CoV-2 variants has raised concern about potential immune escape. In this study, we performed an immunogenicity comparison of ancestral RBD, S1, and S ectodomain trimer (S-trimer) antigens and tested the efficacy of these prototype vaccines against the circulating variants, especially B.1.617 that has been linked to India's current COVID-19 surge. We found that RBD and S-trimer proteins could induce significantly higher neutralizing antibody titers than S1 protein. For the three vaccines, the neutralizing titers decreased over time, but still remained high for at least five months after immunization. Importantly, the three prototype vaccines were still effective in neutralizing the variants of concern, although B.1.351 and B.1.617.1 lineages showed varying degrees of reduction in neutralization by the immune sera. The vaccines-induced sera were shown to block receptor binding and inhibit S protein-mediated membrane fusion. In addition, the immune sera did not promote antibody-dependent enhancement (ADE) in vitro. Our work provides valuable information for development of SARS-CoV-2 subunit vaccines and also supports the continued use of ancestral RBD or S-based vaccines to fight the COVID-19 epidemic.

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 Structure of Severe Acute Respiratory Syndrome Coronavirus Receptor-binding Domain Complexed with Neutralizing Antibody

2006 ◽  
Vol 281 (23) ◽  
pp. 15829-15836 ◽  
Author(s):  
Ponraj Prabakaran ◽  
Jianhua Gan ◽  
Yang Feng ◽  
Zhongyu Zhu ◽  
Vidita Choudhry ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Receptor Binding Domain

Discovery of potential inhibitors of the receptor-binding domain (RBD) of pandemic disease-causing SARS-CoV-2 Spike Glycoprotein from Triphala through molecular docking

2021 ◽  
Vol 01 ◽  
Author(s):  
Sharuk L. Khan ◽  
Falak A. Siddiqui ◽  
Mohd Sayeed Shaikh ◽  
Nitin V. Nema ◽  
Aijaz A. Shaikh
Keyword(s):  
Molecular Docking ◽  
Hydrogen Bonds ◽  
Receptor Binding ◽  
Chemical Constituents ◽  
Antioxidant Properties ◽  
Binding Domain ◽  
Quality Data ◽  
Receptor Binding Domain ◽  
Spike Glycoprotein

Background: COVID-19 (SARS-CoV-2 infection) has affected almost every region of the world. Presently, there is no defined line of treatment available for it. Triphala is already proven to have a safe biological window and well known for its antioxidant and immunomodulatory properties. Objective: Present work has been carried out to study Triphala's effectiveness for the treatment of COVID-19. Methods: The Receptor-binding domain (RBD) of SARS-CoV-2 Spike Glycoprotein responsible for the invasion into the host cell, which leads to further infection. The molecular docking (MD) was performed to explore the binding affinities (kcal/mol) of Triphala's chemical constituents and compared them with the existing drugs under investigation for the treatment of COVID-19 epidemiology. Results: Chebulinic acid binding affinity -8.5 kcal/mol with the formation of 10 hydrogen bonds. Almost all the major chemical constituents have formed two or more hydrogen bonds with RBD of SARS-CoV-2 Spike Glycoprotein. Conclusion: The present study showed that Triphala might perform vital roles in the treatment of COVID-19 and expand its usefulness to physicians to treat this illness. There is a need to complete the in-vitro, in-vivo biological testing of Triphala on SARS-CoV-2 disease to create more quality data. The binding mode of Chebulinic acid in the allosteric cavity allows a better understanding of RBD of SARS-CoV-2 Spike Glycoprotein target and provides insight for the design of new inhibitors. Triphala is already proven to have a safe biological window, which indicates we can skip the pre-clinical trials. Apart from this, Triphala is well known for its antioxidant properties, which ultimately improves the immunity of the COVID-19 patient.

scholarly journals Cross-reactive neutralization of SARS-CoV-2 by serum antibodies from recovered SARS patients and immunized animals

2020 ◽  
Vol 6 (45) ◽  
pp. eabc9999 ◽  
Author(s):  
Yuanmei Zhu ◽  
Danwei Yu ◽  
Yang Han ◽  
Hongxia Yan ◽  
Huihui Chong ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Binding Domain ◽  
Full Length ◽  
Receptor Binding Domain ◽  
Serum Antibodies ◽  
Serum Samples ◽  
S Protein ◽  
Novel Coronavirus

The current coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus genetically close to SARS-CoV. To investigate the effects of previous SARS-CoV infection on the ability to recognize and neutralize SARS-CoV-2, we analyzed 20 convalescent serum samples collected from individuals infected with SARS-CoV during the 2003 SARS outbreak. All patient sera reacted strongly with the S1 subunit and receptor binding domain (RBD) of SARS-CoV; cross-reacted with the S ectodomain, S1, RBD, and S2 proteins of SARS-CoV-2; and neutralized both SARS-CoV and SARS-CoV-2 S protein–driven infections. Analysis of antisera from mice and rabbits immunized with a full-length S and RBD immunogens of SARS-CoV verified cross-reactive neutralization against SARS-CoV-2. A SARS-CoV–derived RBD from palm civets elicited more potent cross-neutralizing responses in immunized animals than the RBD from a human SARS-CoV strain, informing strategies for development of universal vaccines against emerging coronaviruses.

scholarly journals Identification of Common Deletions in the Spike Protein of Severe Acute Respiratory Syndrome Coronavirus 2

2020 ◽  
Vol 94 (17) ◽  
Author(s):  
Zhe Liu ◽  
Huanying Zheng ◽  
Huifang Lin ◽  
Mingyue Li ◽  
Runyu Yuan ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Virus Replication ◽  
Receptor Binding ◽  
Cleavage Site ◽  
Spike Protein ◽  
Clinical Samples ◽  
Receptor Binding Domain ◽  
Flanking Sequence

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus first identified in December 2019. Notable features that make SARS-CoV-2 distinct from most other previously identified betacoronaviruses include a receptor binding domain and a unique insertion of 12 nucleotides or 4 amino acids (PRRA) at the S1/S2 boundary. In this study, we identified two deletion variants of SARS-CoV-2 that either directly affect the polybasic cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN). These deletions were verified by multiple sequencing methods. In vitro results showed that the deletion of NSPRRAR likely does not affect virus replication in Vero and Vero-E6 cells; however, the deletion of QTQTN may restrict late-phase viral replication. The deletion of QTQTN was detected in 3 of 68 clinical samples and 12 of 24 in vitro-isolated viruses, while the deletion of NSPRRAR was identified in 3 in vitro-isolated viruses. Our data indicate that (i) there may be distinct selection pressures on SARS-CoV-2 replication or infection in vitro and in vivo; (ii) an efficient mechanism for deleting this region from the viral genome may exist, given that the deletion variant is commonly detected after two rounds of cell passage; and (iii) the PRRA insertion, which is unique to SARS-CoV-2, is not fixed during virus replication in vitro. These findings provide information to aid further investigation of SARS-CoV-2 infection mechanisms and a better understanding of the NSPRRAR deletion variant observed here. IMPORTANCE The spike protein determines the infectivity and host range of coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has two unique features in its spike protein, the receptor binding domain and an insertion of 12 nucleotides at the S1/S2 boundary resulting in a furin-like cleavage site. Here, we identified two deletion variants of SARS-CoV-2 that either directly affect the furin-like cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN), and we investigated these deletions in cell isolates and clinical samples. The absence of the polybasic cleavage site in SARS-CoV-2 did not affect virus replication in Vero or Vero-E6 cells. Our data indicate the PRRAR sequence and the flanking QTQTN sequence are not fixed in vitro; thus, there appears to be distinct selection pressures on SARS-CoV-2 sequences in vitro and in vivo. Further investigation of the mechanism of generating these deletion variants and their infectivity in different animal models would improve our understanding of the origin and evolution of this virus.

scholarly journals Structural classification of neutralizing antibodies against the SARS-CoV-2 spike receptor-binding domain suggests vaccine and therapeutic strategies

2020 ◽  
Author(s):  
Christopher O. Barnes ◽  
Claudia A. Jette ◽  
Morgan E. Abernathy ◽  
Kim-Marie A. Dam ◽  
Shannon R. Esswein ◽  
...  
Keyword(s):  
Immune Responses ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Health Crisis ◽  
Naturally Occurring ◽  
Insight Into

AbstractThe COVID-19 pandemic presents an urgent health crisis. Human neutralizing antibodies (hNAbs) that target the host ACE2 receptor-binding domain (RBD) of the SARS-CoV-2 spike1–5 show therapeutic promise and are being evaluated clincally6–8. To determine structural correlates of SARS-CoV-2 neutralization, we solved 8 new structures of distinct COVID-19 hNAbs5 in complex with SARS-CoV-2 spike trimer or RBD. Structural comparisons allowed classification into categories: (1) VH3-53 hNAbs with short CDRH3s that block ACE2 and bind only to “up” RBDs, (2) ACE2-blocking hNAbs that bind both “up” and “down” RBDs and can contact adjacent RBDs, (3) hNAbs that bind outside the ACE2 site and recognize “up” and “down” RBDs, and (4) Previously-described antibodies that do not block ACE2 and bind only “up” RBDs9. Class 2 comprised four hNAbs whose epitopes bridged RBDs, including a VH3-53 hNAb that used a long CDRH3 with a hydrophobic tip to bridge between adjacent “down” RBDs, thereby locking spike into a closed conformation. Epitope/paratope mapping revealed few interactions with host-derived N-glycans and minor contributions of antibody somatic hypermutations to epitope contacts. Affinity measurements and mapping of naturally-occurring and in vitro-selected spike mutants in 3D provided insight into the potential for SARS-CoV-2 escape from antibodies elicited during infection or delivered therapeutically. These classifications and structural analyses provide rules for assigning current and future human RBD-targeting antibodies into classes, evaluating avidity effects, suggesting combinations for clinical use, and providing insight into immune responses against SARS-CoV-2.

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