scholarly journals High resolution linear epitope mapping of the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 mRNA vaccine recipients.

2021 ◽  
Author(s):  
Yuko Nitahara ◽  
Yu Nakagama ◽  
Natsuko Kaku ◽  
Katherine Candray ◽  
Yu Michimuko ◽  
...  
Keyword(s):  
High Resolution ◽  
Receptor Binding ◽  
Messenger Rna ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Spike Protein ◽  
Linear Epitope ◽  
Receptor Binding Domain ◽  
Population Immunity

The prompt rollout of the coronavirus disease (COVID-19) messenger RNA (mRNA) vaccine facilitated population immunity, which shall become more dominant than natural infection-induced immunity. At the beginning of the vaccine era, the initial epitope profile in naive individuals will be the first step to build an optimal host defense system towards vaccine-based population immunity. In this study, the high-resolution linear epitope profiles between Pfizer-BioNTech COVID-19 mRNA vaccine recipients and COVID-19 patients were delineated by using microarrays mapped with overlapping peptides of the receptor binding domain (RBD) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. The vaccine-induced antibodies targeting RBD had broader distribution across the RBD than that induced by the natural infection. The relatively lower neutralizing antibody titers observed in vaccine-induced sera could attribute to less efficient epitope selection and maturation of the vaccine-induced humoral immunity compared to the infection-induced. Furthermore, additional mutation panel assays showed that the vaccine-induced rich epitope variety targeting the RBD may aid antibodies to escape rapid viral evolution, which could grant an advantage to the vaccine immunity.

scholarly journals High-Resolution Linear Epitope Mapping of the Receptor Binding Domain of SARS-CoV-2 Spike Protein in COVID-19 mRNA Vaccine Recipients

2021 ◽  
Author(s):  
Yuko Nitahara ◽  
Yu Nakagama ◽  
Natsuko Kaku ◽  
Katherine Candray ◽  
Yu Michimuko ◽  
...  
Keyword(s):  
High Resolution ◽  
Receptor Binding ◽  
Epitope Mapping ◽  
Binding Domain ◽  
Spike Protein ◽  
Linear Epitope ◽  
Receptor Binding Domain ◽  
Population Immunity ◽  
Herd Protection ◽  
Key Factor

Establishing vaccine-based population immunity has been the key factor in attaining herd protection. Thanks to expedited worldwide research efforts, the potency of mRNA vaccines against the coronavirus disease 2019 (COVID-19) is now incontestable.

scholarly journals Combining a Fusion Inhibitory Peptide Targeting the MERS-CoV S2 Protein HR1 Domain and a Neutralizing Antibody Specific for the S1 Protein Receptor-Binding Domain (RBD) Showed Potent Synergism against Pseudotyped MERS-CoV with or without Mutations in RBD

Viruses ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 31 ◽  
Author(s):  
Cong Wang ◽  
Chen Hua ◽  
Shuai Xia ◽  
Weihua Li ◽  
Lu Lu ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Inhibitory Peptide ◽  
Protein Receptor ◽  
Neutralizing Monoclonal Antibody ◽  
Peptide Targeting ◽  
Combinatorial Strategy

Middle East respiratory syndrome coronavirus (MERS-CoV) has continuously posed a threat to public health worldwide, yet no therapeutics or vaccines are currently available to prevent or treat MERS-CoV infection. We previously identified a fusion inhibitory peptide (HR2P-M2) targeting the MERS-CoV S2 protein HR1 domain and a highly potent neutralizing monoclonal antibody (m336) specific to the S1 spike protein receptor-binding domain (RBD). However, m336 was found to have reduced efficacy against MERS-CoV strains with mutations in RBD, and HR2P-M2 showed low potency, thus limiting the clinical application of each when administered separately. However, we herein report that the combination of m336 and HR2P-M2 exhibited potent synergism in inhibiting MERS-CoV S protein-mediated cell–cell fusion and infection by MERS-CoV pseudoviruses with or without mutations in the RBD, resulting in the enhancement of antiviral activity in contrast to either one administered alone. Thus, this combinatorial strategy could be used in clinics for the urgent treatment of MERS-CoV-infected patients.

scholarly journals Polymersomes decorated with SARS-CoV-2 spike protein receptor binding domain elicit robust humoral and cellular immunity

2021 ◽  
Author(s):  
Lisa R Volpatti ◽  
Rachel P Wallace ◽  
Shijie Cao ◽  
Michal Raczy ◽  
Ruyi Wang ◽  
...  
Keyword(s):  
T Cell ◽  
Antibody Response ◽  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Vaccination Site ◽  
Monophosphoryl Lipid A ◽  
Protein Receptor

A diverse portfolio of SARS-CoV-2 vaccine candidates is needed to combat the evolving COVID-19 pandemic. Here, we developed a subunit nanovaccine by conjugating SARS-CoV-2 Spike protein receptor binding domain (RBD) to the surface of oxidation-sensitive polymersomes. We evaluated the humoral and cellular responses of mice immunized with these surface-decorated polymersomes (RBDsurf) compared to RBD-encapsulated polymersomes (RBDencap) and unformulated RBD (RBDfree), using monophosphoryl lipid A-encapsulated polymersomes (MPLA PS) as an adjuvant. While all three groups produced high titers of RBD-specific IgG, only RBDsurf elicited a neutralizing antibody response to SARS-CoV-2 comparable to that of human convalescent plasma. Moreover, RBDsurf was the only group to significantly increase the proportion of RBD-specific germinal center B cells in the vaccination-site draining lymph nodes. Both RBDsurf and RBDencap drove similarly robust CD4+ and CD8+ T cell responses that produced multiple Th1-type cytokines. We conclude that multivalent surface display of Spike RBD on polymersomes promotes a potent neutralizing antibody response to SARS-CoV-2, while both antigen formulations promote robust T cell immunity.

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.

Escape of SARS-CoV-2 501Y.V2 variants from neutralization by convalescent plasma

2021 ◽  
Author(s):  
Sandile Cele ◽  
Inbal Gazy ◽  
Laurelle Jackson ◽  
Shi-Hsia Hwa ◽  
Houriiyah Tegally ◽  
...  
Keyword(s):  
South Africa ◽  
Antibody Response ◽  
Genome Sequencing ◽  
Receptor Binding ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Spike Protein ◽  
Whole Genome ◽  
Receptor Binding Domain ◽  
Neutralization Activity

AbstractNew SARS-CoV-2 variants with mutations in the spike glycoprotein have arisen independently at multiple locations and may have functional significance. The combination of mutations in the 501Y.V2 variant first detected in South Africa include the N501Y, K417N, and E484K mutations in the receptor binding domain (RBD) as well as mutations in the N-terminal domain (NTD). Here we address whether the 501Y.V2 variant could escape the neutralizing antibody response elicited by natural infection with earlier variants. We were the first to outgrow two variants of 501Y.V2 from South Africa, designated 501Y.V2.HV001 and 501Y.V2.HVdF002. We examined the neutralizing effect of convalescent plasma collected from six adults hospitalized with COVID-19 using a microneutralization assay with live (authentic) virus. Whole genome sequencing of the infecting virus of the plasma donors confirmed the absence of the spike mutations which characterize 501Y.V2. We infected with 501Y.V2.HV001 and 501Y.V2.HVdF002 and compared plasma neutralization to first wave virus which contained the D614G mutation but no RBD or NTD mutations. We observed that neutralization of the 501Y.V2 variants was strongly attenuated, with IC50 6 to 200-fold higher relative to first wave virus. The degree of attenuation varied between participants and included a knockout of neutralization activity. This observation indicates that 501Y.V2 may escape the neutralizing antibody response elicited by prior natural infection. It raises a concern of potential reduced protection against re-infection and by vaccines designed to target the spike protein of earlier SARS-CoV-2 variants.

scholarly journals XAV-19, a Swine Glyco-Humanized Polyclonal Antibody Against SARS-CoV-2 Spike Receptor-Binding Domain, Targets Multiple Epitopes and Broadly Neutralizes Variants

2021 ◽  
Vol 12 ◽  
Author(s):  
Bernard Vanhove ◽  
Stéphane Marot ◽  
Ray T. So ◽  
Benjamin Gaborit ◽  
Gwénaëlle Evanno ◽  
...  
Keyword(s):  
South African ◽  
Receptor Binding ◽  
Polyclonal Antibodies ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Live Virus ◽  
Angiotensin Converting Enzyme 2 ◽  
The United Kingdom

Amino acid substitutions and deletions in the Spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants can reduce the effectiveness of monoclonal antibodies (mAbs). In contrast, heterologous polyclonal antibodies raised against S protein, through the recognition of multiple target epitopes, have the potential to maintain neutralization capacities. XAV-19 is a swine glyco-humanized polyclonal neutralizing antibody raised against the receptor binding domain (RBD) of the Wuhan-Hu-1 Spike protein of SARS-CoV-2. XAV-19 target epitopes were found distributed all over the RBD and particularly cover the receptor binding motives (RBMs), in direct contact sites with the angiotensin converting enzyme-2 (ACE-2). Therefore, in Spike/ACE-2 interaction assays, XAV-19 showed potent neutralization capacities of the original Wuhan Spike and of the United Kingdom (Alpha/B.1.1.7) and South African (Beta/B.1.351) variants. These results were confirmed by cytopathogenic assays using Vero E6 and live virus variants including the Brazil (Gamma/P.1) and the Indian (Delta/B.1.617.2) variants. In a selective pressure study on Vero E6 cells conducted over 1 month, no mutation was associated with the addition of increasing doses of XAV-19. The potential to reduce viral load in lungs was confirmed in a human ACE-2 transduced mouse model. XAV-19 is currently evaluated in patients hospitalized for COVID-19-induced moderate pneumonia in phase 2a-2b (NCT04453384) where safety was already demonstrated and in an ongoing 2/3 trial (NCT04928430) to evaluate the efficacy and safety of XAV-19 in patients with moderate-to-severe COVID-19. Owing to its polyclonal nature and its glyco-humanization, XAV-19 may provide a novel safe and effective therapeutic tool to mitigate the severity of coronavirus disease 2019 (COVID-19) including the different variants of concern identified so far.

scholarly journals A Novel Neutralizing Antibody Targeting Receptor Binding Domain of SARS-CoV-2

2020 ◽  
Author(s):  
Soo-Young Lee ◽  
Cheolmin Kim ◽  
Dong-Kyun Ryu ◽  
Jihun Lee ◽  
Young-Il Kim ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Human Monoclonal Antibody ◽  
Substantial Reduction ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Spike Protein ◽  
Enhancement Effect ◽  
Therapeutic Effects ◽  
Receptor Binding Domain ◽  
Protein Variant

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the current COVID-19 global pandemic. Vaccines and therapeutics are urgently needed for this highly transmissible virus. In this study, we screened human monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of the SARS-CoV-2 spike protein from an antibody library constructed from peripheral blood mononuclear cells of a COVID-19 convalescent patient. A potent neutralizing antibody, termed CT-P59, was identified and found to be effective against various SARS-CoV-2 isolates including the D614G spike protein variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/SARS-CoV-2 RBD showed that CT-P59 blocks interaction regions of SARS-CoV-2 RBD for its cellular receptor, angiotensin converting enzyme 2 (ACE2). The binding orientation of CT-P59 is notably different from the previously reported neutralizing mAbs targeting SARS-CoV-2 RBD suggesting that CT-P59 can be a novel binder to SARS-CoV-2 RBD. Therapeutic effects of CT-P59 were evaluated in three animal models (ferret, hamster, and rhesus monkey), and a substantial reduction in viral titre along with alleviation of clinical symptoms was observed. These findings suggest that the human monoclonal antibody, CT-P59, is a promising therapeutic candidate for treatment of COVID-19.

scholarly journals Cryo-EM Structures of the N501Y SARS-CoV-2 Spike Protein in Complex with ACE2 and Two Potent Neutralizing Antibodies

2021 ◽  
Author(s):  
Xing Zhu ◽  
Dhiraj Mannar ◽  
Shanti S. Srivastava ◽  
Alison M. Berezuk ◽  
Jean-Philippe Demers ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Structural Changes ◽  
Neutralizing Antibody ◽  
Antibody Fragments ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Binding Interface ◽  
Short Summary

AbstractThe recently reported “UK variant” of SARS-CoV-2 is thought to be more infectious than previously circulating strains as a result of several changes, including the N501Y mutation. We present a 2.9-Å resolution cryo-EM structure of the complex between the ACE2 receptor and N501Y spike protein ectodomains that shows Y501 inserted into a cavity at the binding interface near Y41 of ACE2. The additional interactions result in increased affinity of ACE2 for the N501Y mutant, accounting for its increased infectivity. However, this mutation does not result in large structural changes, enabling important neutralization epitopes to be retained in the spike receptor binding domain. We confirmed this through biophysical assays and by determining cryo-EM structures of spike protein ectodomains bound to two representative potent neutralizing antibody fragments.Short summaryThe N501Y mutation found in the coronavirus UK variant increases infectivity but some neutralizing antibodies can still bind.

scholarly journals Attenuated Influenza Virions Expressing the SARS-CoV-2 Receptor-Binding Domain Induce Neutralizing Antibodies in Mice

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 987 ◽  
Author(s):  
Andrea N. Loes ◽  
Lauren E. Gentles ◽  
Allison J. Greaney ◽  
Katharine H. D. Crawford ◽  
Jesse D. Bloom
Keyword(s):  
Influenza Virus ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Reverse Genetics ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Effective Vaccine ◽  
Receptor Binding Domain ◽  
Antibody Titers

An effective vaccine is essential for controlling the spread of the SARS-CoV-2 virus. Here, we describe an influenza virus-based vaccine for SARS-CoV-2. We incorporated a membrane-anchored form of the SARS-CoV-2 spike receptor binding domain (RBD) in place of the neuraminidase (NA) coding sequence in an influenza virus also possessing a mutation that reduces the affinity of hemagglutinin for its sialic acid receptor. The resulting ΔNA(RBD)-Flu virus can be generated by reverse genetics and grown to high titers in cell culture. A single-dose intranasal inoculation of mice with ΔNA(RBD)-Flu elicits serum neutralizing antibody titers against SAR-CoV-2 comparable to those observed in humans following natural infection (~1:200). Furthermore, ΔNA(RBD)-Flu itself causes no apparent disease in mice. It might be possible to produce a vaccine similar to ΔNA(RBD)-Flu at scale by leveraging existing platforms for the production of influenza vaccines.

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