scholarly journals Homologous and heterologous serological response to the N-terminal domain of SARS-CoV-2

2021 ◽  
Author(s):  
Huibin Lv ◽  
Owen Tak-Yin Tsang ◽  
Ray T. Y. So ◽  
Yiquan Wang ◽  
Meng Yuan ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Global Economy ◽  
Vaccine Development ◽  
Serological Response ◽  
Receptor Binding Domain ◽  
Plasma Samples ◽  
Mice Model ◽  
Terminal Domain ◽  
Major Antigen ◽  
Serology Testing

SUMMARYThe increasing numbers of infected cases of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses serious threats to public health and the global economy. Most SARS-CoV-2 neutralizing antibodies target the receptor binding domain (RBD) and some the N-terminal domain (NTD) of the spike protein, which is the major antigen of SARS-CoV-2. While the antibody response to RBD has been extensively characterized, the antigenicity and immunogenicity of the NTD protein are less well studied. Using 227 plasma samples from COVID-19 patients, we showed that SARS-CoV-2 NTD-specific antibodies could be induced during infection. As compared to the serological response to SARS-CoV-2 RBD, the SARS-CoV-2 NTD response is less cross-reactive with SARS-CoV. Furthermore, neutralizing antibodies are rarely elicited in a mice model when NTD is used as an immunogen. We subsequently demonstrate that NTD has an altered antigenicity when expressed alone. Overall, our results suggest that while NTD offers an alternative strategy for serology testing, it may not be suitable as an immunogen for vaccine development.

scholarly journals The SARS-CoV-2 Delta variant is poised to acquire complete resistance to wild-type spike vaccines

2021 ◽  
Author(s):  
Yafei Liu ◽  
Noriko Arase ◽  
Jun-ichi Kishikawa ◽  
Mika Hirose ◽  
Songling Li ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Effective Protection ◽  
Neutralizing Activity ◽  
Terminal Domain ◽  
Complete Resistance

AbstractmRNA-based vaccines provide effective protection against most common SARS-CoV-2 variants. However, identifying likely breakthrough variants is critical for future vaccine development. Here, we found that the Delta variant completely escaped from anti-N-terminal domain (NTD) neutralizing antibodies, while increasing responsiveness to anti-NTD infectivity-enhancing antibodies. Although Pfizer-BioNTech BNT162b2-immune sera neutralized the Delta variant, when four common mutations were introduced into the receptor binding domain (RBD) of the Delta variant (Delta 4+), some BNT162b2-immune sera lost neutralizing activity and enhanced the infectivity. Unique mutations in the Delta NTD were involved in the enhanced infectivity by the BNT162b2-immune sera. Sera of mice immunized by Delta spike, but not wild-type spike, consistently neutralized the Delta 4+ variant without enhancing infectivity. Given the fact that a Delta variant with three similar RBD mutations has already emerged according to the GISAID database, it is necessary to develop vaccines that protect against such complete breakthrough variants.

scholarly journals SARS-CoV-2 Vaccines Based on the Spike Glycoprotein and Implications of New Viral Variants

2021 ◽  
Vol 12 ◽  
Author(s):  
Daniel Martínez-Flores ◽  
Jesús Zepeda-Cervantes ◽  
Adolfo Cruz-Reséndiz ◽  
Sergio Aguirre-Sampieri ◽  
Alicia Sampieri ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Clinical Manifestations ◽  
Receptor Binding Domain ◽  
Current Vaccine ◽  
Main Target ◽  
Different Types ◽  
Antigenic Domains

Coronavirus 19 Disease (COVID-19) originating in the province of Wuhan, China in 2019, is caused by the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), whose infection in humans causes mild or severe clinical manifestations that mainly affect the respiratory system. So far, the COVID-19 has caused more than 2 million deaths worldwide. SARS-CoV-2 contains the Spike (S) glycoprotein on its surface, which is the main target for current vaccine development because antibodies directed against this protein can neutralize the infection. Companies and academic institutions have developed vaccines based on the S glycoprotein, as well as its antigenic domains and epitopes, which have been proven effective in generating neutralizing antibodies. However, the emergence of new SARS-CoV-2 variants could affect the effectiveness of vaccines. Here, we review the different types of vaccines designed and developed against SARS-CoV-2, placing emphasis on whether they are based on the complete S glycoprotein, its antigenic domains such as the receptor-binding domain (RBD) or short epitopes within the S glycoprotein. We also review and discuss the possible effectiveness of these vaccines against emerging SARS-CoV-2 variants.

scholarly journals Fast Restoration of a Broad-Spectrum SARS-Cov Therapeutic Antibody for SARS-Cov-2

2020 ◽  
Author(s):  
Sara Zhang ◽  
Mike Young ◽  
Jason Pan
Keyword(s):  
Broad Spectrum ◽  
Neutralizing Antibodies ◽  
Global Economy ◽  
Therapeutic Antibody ◽  
Receptor Binding Domain ◽  
Promising Candidate ◽  
Rapid Spread ◽  
Antibody Design ◽  
Potential Therapeutics ◽  
Conserved Epitope

<p>The rapid spread of SARS-Cov-2 remains a major threat for public health and global economy, both preventative and therapeutic solutions are therefore urgently needed. Through the use of epitope-guided antibody design, we successfully restored a broad-spectrum SARS-Cov therapeutic antibody for SARS-Cov-2. Compared to the precursor antibody CR3022, the newly designed antibody NOVOAB-20 binds to SARS-Cov-2 receptor binding domain (RBD) with a more than 10-fold higher affinity. Because this antibody targets a highly conserved epitope and the mutations on SARS-Cov-2 known so far are all not in this region, it also has the potential to block future SARS-Cov-2 mutants. As a fully humanized antibody, NOVOAB-20 is a promising candidate to be developed as potential therapeutics for SARS-Cov-2, either as monotherapy or in combination with other neutralizing antibodies targeting different epitopes (e.g. the ACE2 binding site).</p>

scholarly journals N-terminal domain antigenic mapping reveals a site of vulnerability for SARS-CoV-2

2021 ◽  
Author(s):  
Matthew McCallum ◽  
Anna De Marco ◽  
Florian Lempp ◽  
M. Alejandra Tortorici ◽  
Dora Pinto ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Selective Pressure ◽  
Memory B Cells ◽  
Host Cells ◽  
Receptor Binding Domain ◽  
Effector Functions ◽  
Terminal Domain ◽  
Frequent Mutations ◽  
A Site

SARS-CoV-2 entry into host cells is orchestrated by the spike (S) glycoprotein that contains an immunodominant receptor-binding domain (RBD) targeted by the largest fraction of neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge. SARS-CoV-2 variants, including the 501Y.V2 and B.1.1.7 lineages, harbor frequent mutations localized in the NTD supersite suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs to protective immunity.

scholarly journals Recombinant Antigens Based on Non-Glycosylated Regions from RBD SARS-CoV-2 as Potential Vaccine Candidates against COVID-19

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 928
Author(s):  
Leandro Núñez-Muñoz ◽  
Gabriel Marcelino-Pérez ◽  
Berenice Calderón-Pérez ◽  
Miriam Pérez-Saldívar ◽  
Karla Acosta-Virgen ◽  
...  
Keyword(s):  
Immune Response ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Polyclonal Antibodies ◽  
Igg Antibodies ◽  
Mice Model ◽  
Strong Immune Response ◽  
Recombinant Antigens ◽  
Glycosylation Sites ◽  
Potential Vaccine

The Receptor-Binding Domain (RBD) of the Spike (S) protein from Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has glycosylation sites which can limit the production of reliable antigens expressed in prokaryotic platforms, due to glycan-mediated evasion of the host immune response. However, protein regions without glycosylated residues capable of inducing neutralizing antibodies could be useful for antigen production in systems that do not carry the glycosylation machinery. To test this hypothesis, the potential antigens NG06 and NG19, located within the non-glycosylated S-RBD region, were selected and expressed in Escherichia coli, purified by FPLC and employed to determine their immunogenic potential through detection of antibodies in serum from immunized rabbits, mice, and COVID-19 patients. IgG antibodies from sera of COVID-19-recovered patients detected the recombinant antigens NG06 and NG19 (A450 nm = 0.80 ± 0.33; 1.13 ± 0.33; and 0.11 ± 0.08 for and negatives controls, respectively). Also, the purified antigens were able to raise polyclonal antibodies in animal models evoking a strong immune response with neutralizing activity in mice model. This research highlights the usefulness of antigens based on the non-N-glycosylated region of RBD from SARS-CoV-2 for candidate vaccine development.

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 Comparative Immunogenicity of the Recombinant Receptor-Binding Domain of Protein S SARS-CoV-2 Obtained in Prokaryotic and Mammalian Expression Systems

Vaccines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 96
Author(s):  
Iuliia A. Merkuleva ◽  
Dmitry N. Shcherbakov ◽  
Mariya B. Borgoyakova ◽  
Daniil V. Shanshin ◽  
Andrey P. Rudometov ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Expression System ◽  
Protein S ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Expression Systems ◽  
Mice Model ◽  
Mammalian Expression ◽  
Recombinant Receptor

The receptor-binding domain (RBD) of the protein S SARS-CoV-2 is considered to be one of the appealing targets for developing a vaccine against COVID-19. The choice of an expression system is essential when developing subunit vaccines, as it ensures the effective synthesis of the correctly folded target protein, and maintains its antigenic and immunogenic properties. Here, we describe the production of a recombinant RBD protein using prokaryotic (pRBD) and mammalian (mRBD) expression systems, and compare the immunogenicity of prokaryotic and mammalian-expressed RBD using a BALB/c mice model. An analysis of the sera from mice immunized with both variants of the protein revealed that the mRBD expressed in CHO cells provides a significantly stronger humoral immune response compared with the RBD expressed in E.coli cells. A specific antibody titer of sera from mice immunized with mRBD was ten-fold higher than the sera from the mice that received pRBD in ELISA, and about 100-fold higher in a neutralization test. The data obtained suggests that mRBD is capable of inducing neutralizing antibodies against SARS-CoV-2.

scholarly journals The receptor binding domain of SARS-CoV-2 spike is the key target of neutralizing antibody in human polyclonal sera

2020 ◽  
Author(s):  
Tara L. Steffen ◽  
E. Taylor Stone ◽  
Mariah Hassert ◽  
Elizabeth Geerling ◽  
Brian T. Grimberg ◽  
...  
Keyword(s):  
Antibody Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Antigenic Determinants ◽  
Receptor Binding Domain ◽  
Neutralization Capacity

AbstractNatural infection of SARS-CoV-2 in humans leads to the development of a strong neutralizing antibody response, however the immunodominant targets of the polyclonal neutralizing antibody response are still unknown. Here, we functionally define the role SARS-CoV-2 spike plays as a target of the human neutralizing antibody response. In this study, we identify the spike protein subunits that contain antigenic determinants and examine the neutralization capacity of polyclonal sera from a cohort of patients that tested qRT-PCR-positive for SARS-CoV-2. Using an ELISA format, we assessed binding of human sera to spike subunit 1 (S1), spike subunit 2 (S2) and the receptor binding domain (RBD) of spike. To functionally identify the key target of neutralizing antibody, we depleted sera of subunit-specific antibodies to determine the contribution of these individual subunits to the antigen-specific neutralizing antibody response. We show that epitopes within RBD are the target of a majority of the neutralizing antibodies in the human polyclonal antibody response. These data provide critical information for vaccine development and development of sensitive and specific serological testing.

scholarly journals Elicitation of broadly protective sarbecovirus immunity by receptor-binding domain nanoparticle vaccines

2021 ◽  
Author(s):  
Alexandra C Walls ◽  
Marcos C Miranda ◽  
Minh N Pham ◽  
Alexandra Schaefer ◽  
Allison Greaney ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Polyclonal Antibodies ◽  
Clinical Stage ◽  
Binding Domain ◽  
Single Shot ◽  
Receptor Binding Domain ◽  
Negative Consequences ◽  
Neutralizing Activity

Understanding the ability of SARS-CoV-2 vaccine-elicited antibodies to neutralize and protect against emerging variants of concern and other sarbecoviruses is key for guiding vaccine development decisions and public health policies. We show that a clinical stage multivalent SARS-CoV-2 receptor-binding domain nanoparticle vaccine (SARS-CoV-2 RBD-NP) protects mice from SARS-CoV-2-induced disease after a single shot, indicating that the vaccine could allow dose-sparing. SARS-CoV-2 RBD-NP elicits high antibody titers in two non-human primate (NHP) models against multiple distinct RBD antigenic sites known to be recognized by neutralizing antibodies. We benchmarked NHP serum neutralizing activity elicited by RBD-NP against a lead prefusion-stabilized SARS-CoV-2 spike immunogen using a panel of single-residue spike mutants detected in clinical isolates as well as the B.1.1.7 and B.1.351 variants of concern. Polyclonal antibodies elicited by both vaccines are resilient to most RBD mutations tested, but the E484K substitution has similar negative consequences for neutralization, and exhibit modest but comparable neutralization breadth against distantly related sarbecoviruses. We demonstrate that mosaic and cocktail sarbecovirus RBD-NPs elicit broad sarbecovirus neutralizing activity, including against the SARS-CoV-2 B.1.351 variant, and protect mice against severe SARS-CoV challenge even in the absence of the SARS-CoV RBD in the vaccine. This study provides proof of principle that sarbecovirus RBD-NPs induce heterotypic protection and enables advancement of broadly protective sarbecovirus vaccines to the clinic.

scholarly journals A Recombinant Protein SARS-CoV-2 Candidate Vaccine Elicits High-titer Neutralizing Antibodies in Macaques.

2021 ◽  
Author(s):  
Gary Baisa ◽  
David Rancour ◽  
Keith Mansfield ◽  
Monika Burns ◽  
Lori Martin ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
High Titer ◽  
Binding Domain ◽  
Pseudotyped Virus ◽  
Receptor Binding Domain ◽  
Binding Assays ◽  
Neutralizing Activity ◽  
Terminal Domain

Abstract BackgroundVaccines that generate robust and long-lived protective immunity against SARS-CoV-2 infection are urgently required. MethodsWe assessed the potential of vaccine candidates based on the SARS-CoV-2 spike in cynomolgus macaques (M. fascicularis) by examining their ability to generate spike binding antibodies with neutralizing activity. Antigens were derived from two distinct regions of the spike S1 subunit, either the N-terminal domain or an extended C-terminal domain containing the receptor-binding domain and were fused to the human IgG1 Fc domain. Three groups of 2 animals each were immunized with either antigen, alone or in combination. The development of antibody responses was evaluated through 20 weeks post-immunization. ResultsA robust IgG response to the spike protein was detected as early as 2 weeks after immunization with either protein and maintained for over 20 weeks. Sera from animals immunized with antigens derived from the RBD were able to prevent binding of soluble spike proteins to the ACE2 receptor, shown by in vitro binding assays, while sera from animals immunized with the N-terminal domain alone lacked this activity. Crucially, sera from animals immunized with the extended receptor binding domain but not the N-terminal domain had potent neutralizing activity against SARS-CoV-2 pseudotyped virus, with titers in excess of 10,000, greatly exceeding that typically found in convalescent humans. Neutralizing activity persisted for more than 20 weeks. ConclusionsThese data support the utility of spike subunit-based antigens as a vaccine for use in humans.

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