scholarly journals Immunodominant B cell epitope in SARS-CoV-2 RBD comprises a B.1.351 and P.1 mutation hotspot: implications for viral spread and antibody escape

2021 ◽  
Author(s):  
Keity Souza Santos ◽  
Jamille Ramos Oliveira ◽  
Rafael Rahal G. Machado ◽  
Helen Andrade Arcuri ◽  
Jhosiene Yukari Magawa ◽  
...  
Keyword(s):  
B Cell ◽  
Neutralizing Antibodies ◽  
Immune Escape ◽  
Cell Epitope ◽  
Antibody Binding ◽  
Published Data ◽  
Immunodominant Epitope ◽  
Marked Rise ◽  
Viral Spread ◽  
Iga Antibody

AbstractRecent SARS-CoV-2 variants pose important concerns due to their higher transmissibility (1) and escape (2) from previous infections or vaccine-induced neutralizing antibodies (nAb). The receptor binding domain (RBD) of the Spike protein is a major nAb target (3), but data on its B cell epitopes are still lacking. Using a peptide microarray, we identified an immunodominant epitope (S415-429) recognized by 68% of sera from 71 convalescent Brazilians infected with the ancestral variant. In contrast with previous studies, we have identified a linear IgG and IgA antibody binding epitope within the RBD. IgG and IgA antibody levels for this epitope positively correlated with nAb titers, suggesting a potential target of antibody neutralizing activity. Interestingly, this immunodominant RBD region harbors the mutation hotspot site K417 present in P.1 (K417T) and B.1.351 (K417N) variants. In silico simulation analyses indicate impaired RBD binding to nAb in both variants and that a glycosylation in the B.1.351 417N could further hinder antibody binding as compared to the K417T mutation in P.1. This is in line with published data showing that nAb from either convalescents or anti-CoV-2 vaccinees are less effective towards B.1.351 than for P.1. Our data support the occurrence of immune pressure and selection involving this immunodominant epitope that may have critically contributed to the recent COVID-19 marked rise in Brazil and South Africa, and pinpoint a potential additional immune escape mechanism for SARS-CoV-2.

scholarly journals B Epitope Multiplicity and B/T Epitope Orientation Influence Immunogenicity of Foot-and-Mouth Disease Peptide Vaccines

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Esther Blanco ◽  
Carolina Cubillos ◽  
Noelia Moreno ◽  
Juan Bárcena ◽  
Beatriz G. de la Torre ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Cell Epitope ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
T Cell Epitope ◽  
T Cell Epitopes ◽  
B Cell Epitope ◽  
Foot And Mouth

Synthetic peptides incorporating protective B- and T-cell epitopes are candidates for new safer foot-and-mouth disease (FMD) vaccines. We have reported that dendrimeric peptides including four copies of a B-cell epitope (VP1 136 to 154) linked to a T-cell epitope (3A 21 to 35) of FMD virus (FMDV) elicit potent B- and T-cell specific responses and confer protection to viral challenge, while juxtaposition of these epitopes in a linear peptide induces less efficient responses. To assess the relevance of B-cell epitope multivalency, dendrimers bearing two (B2T) or four (B4T) copies of the B-cell epitope from type O FMDV (a widespread circulating serotype) were tested in CD1 mice and showed that multivalency is advantageous over simple B-T-epitope juxtaposition, resulting in efficient induction of neutralizing antibodies and optimal release of IFNγ. Interestingly, the bivalent B2T construction elicited similar or even better B- and T-cell specific responses than tetravalent B4T. In addition, the presence of the T-cell epitope and its orientation were shown to be critical for the immunogenicity of the linear juxtaposed monovalent peptides analyzed in parallel. Taken together, our results provide useful insights for a more accurate design of FMD subunit vaccines.

scholarly journals Convergent Evolution of Neutralizing Antibodies to Staphylococcus aureus γ-Hemolysin C That Recognize an Immunodominant Primary Sequence-Dependent B-Cell Epitope

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
David N. Hernandez ◽  
Kayan Tam ◽  
Bo Shopsin ◽  
Emily E. Radke ◽  
Karen Law ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Phage Display ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Ex Vivo ◽  
Cell Epitope ◽  
Phage Display Library ◽  
Structural Basis ◽  
Peptide Fragments ◽  
Content Type

ABSTRACT Staphylococcus aureus infection is a major public health threat in part due to the spread of antibiotic resistance and repeated failures to develop a protective vaccine. Infection is associated with production of virulence factors that include exotoxins that attack host barriers and cellular defenses, such as the leukocidin (Luk) family of bicomponent pore-forming toxins. To investigate the structural basis of antibody-mediated functional inactivation of Luk toxins, we generated a panel of murine monoclonal antibodies (MAbs) that neutralize host cell killing by the γ-hemolysin HlgCB. By biopanning these MAbs against a phage-display library of random Luk peptide fragments, we identified a small subregion within the rim domain of HlgC as the epitope for all the MAbs. Within the native holotoxin, this subregion folds into a conserved β-hairpin structure, with exposed key residues, His252 and Tyr253, required for antibody binding. On the basis of the phage-display results and molecular modeling, a 15-amino-acid synthetic peptide representing the minimal epitope on HlgC (HlgC241-255) was designed, and preincubation with this peptide blocked antibody-mediated HIgCB neutralization. Immunization of mice with HlgC241-255 or the homologous LukS246-260 subregion peptide elicited serum antibodies that specifically recognized the native holotoxin subunits. Furthermore, serum IgG from patients who were convalescent for invasive S. aureus infection showed neutralization of HlgCB toxin activity ex vivo, which recognized the immunodominant HlgC241-255 peptide and was dependent on His252 and Tyr253 residues. We have thus validated an efficient, rapid, and scalable experimental workflow for identification of immunodominant and immunogenic leukotoxin-neutralizing B-cell epitopes that can be exploited for new S. aureus-protective vaccines and immunotherapies.

scholarly journals Identification of four linear B-cell epitopes on the SARS-CoV-2 spike protein able to elicit neutralizing antibodies

2020 ◽  
Author(s):  
Lin Li ◽  
Zhongpeng Zhao ◽  
Xiaolan Yang ◽  
WenDong Li ◽  
Shaolong Chen ◽  
...  
Keyword(s):  
B Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Epitope ◽  
Effective Vaccine ◽  
B Cell Epitopes ◽  
S Protein ◽  
The Public ◽  
B Cell Epitope ◽  
Linear B

SARS-CoV-2 unprecedentedly threatens the public health at worldwide level. There is an urgent need to develop an effective vaccine within a highly accelerated time. Here, we present the most comprehensive S-protein-based linear B-cell epitope candidate list by combining epitopes predicted by eight widely-used immune-informatics methods with the epitopes curated from literature published between Feb 6, 2020 and July 10, 2020. We find four top prioritized linear B-cell epitopes in the hotspot regions of S protein can specifically bind with serum antibodies from horse, mouse, and monkey inoculated with different SARS-CoV-2 vaccine candidates or a patient recovering from COVID-19. The four linear B-cell epitopes can induce neutralizing antibodies against both pseudo and live SARS-CoV-2 virus in immunized wild-type BALB/c mice. This study suggests that the four linear B-cell epitopes are potentially important candidates for serological assay or vaccine development.

scholarly journals Novel differential linear B-cell epitopes to identify Zika and dengue virus infections in patients

2019 ◽  
Author(s):  
Siti Naqiah Amrun ◽  
Wearn-Xin Yee ◽  
Farhana Abu Bakar ◽  
Bernett Lee ◽  
Yiu-Wing Kam ◽  
...  
Keyword(s):  
B Cell ◽  
Neutralizing Antibodies ◽  
Cell Epitope ◽  
Structural Similarity ◽  
Amino Acid Residues ◽  
Virus Infections ◽  
Protein Amino Acid ◽  
B Cell Epitopes ◽  
Diagnostic Standards ◽  
Linear B

AbstractBackgroundRecent Zika virus (ZIKV) outbreaks challenged existing laboratory diagnostic standards, especially for serology-based methods. Due to the genetic and structural similarity of ZIKV with other flaviviruses, this results in cross-reactive antibodies which confounds serological interpretations.MethodsPlasma from Singapore ZIKV patients was screened longitudinally for antibody responses and neutralizing capacities against ZIKV. Samples from healthy controls, ZIKV and DENV patients were further assessed using ZIKV and DENV peptides of precursor membrane (prM), envelope (E) or non-structural 1 (NS1) viral proteins in a peptide-based ELISA for epitope identification. Identified epitopes were re-validated and diagnostically evaluated using sera of patients with DENV, bacteria or unknown infections from Thailand.ResultsLong-lasting ZIKV-neutralizing antibodies were elicited during ZIKV infection. Thirteen potential linear B-cell epitopes were identified and of these, four common flavivirus, three ZIKV-specific, and one DENV-specific differential epitopes had more than 50% sensitivities and specificities. Notably, ZIKV-specific peptide 26 on domain I/II of E protein (amino acid residues 271-288) presented 80% sensitivity and 85.7% specificity. Importantly, the differential epitopes also showed significance in differentiating non-flavivirus patient samples.ConclusionsLinear B-cell epitope candidates to differentiate ZIKV and DENV infections were identified, providing the first step towards the design of a much-needed serology-based assay.

scholarly journals In silico analysis suggests less effective MHC-II presentation of SARS-CoV-2 RBM peptides: Implication for neutralizing antibody responses

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246731
Author(s):  
Andrea Castro ◽  
Kivilcim Ozturk ◽  
Maurizio Zanetti ◽  
Hannah Carter
Keyword(s):  
T Cell ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Cell Epitope ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Binding Motif ◽  
T Cell Epitopes ◽  
Mhc Ii ◽  
B Cell Epitope

SARS-CoV-2 antibodies develop within two weeks of infection, but wane relatively rapidly post-infection, raising concerns about whether antibody responses will provide protection upon re-exposure. Here we revisit T-B cooperation as a prerequisite for effective and durable neutralizing antibody responses centered on a mutationally constrained RBM B cell epitope. T-B cooperation requires co-processing of B and T cell epitopes by the same B cell and is subject to MHC-II restriction. We evaluated MHC-II constraints relevant to the neutralizing antibody response to a mutationally-constrained B cell epitope in the receptor binding motif (RBM) of the spike protein. Examining common MHC-II alleles, we found that peptides surrounding this key B cell epitope are predicted to bind poorly, suggesting a lack MHC-II support in T-B cooperation, impacting generation of high-potency neutralizing antibodies in the general population. Additionally, we found that multiple microbial peptides had potential for RBM cross-reactivity, supporting previous exposures as a possible source of T cell memory.

scholarly journals Identification of COVID-19 B-cell epitopes with phage-displayed peptide library

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Jing-You Guo ◽  
I-Ju Liu ◽  
Hsiu-Ting Lin ◽  
Mei-Jung Wang ◽  
Yu-Ling Chang ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Epitope ◽  
Epitope Prediction ◽  
Antibody Binding ◽  
Diagnostic Tools ◽  
Serological Detection ◽  
Phage Display Technology ◽  
B Cell Epitopes ◽  
Care Systems ◽  
Phage Displayed Peptide Library

Abstract Background Coronavirus disease 19 (COVID-19) first appeared in the city of Wuhan, in the Hubei province of China. Since its emergence, the COVID-19-causing virus, SARS-CoV-2, has been rapidly transmitted around the globe, overwhelming the medical care systems in many countries and leading to more than 3.3 million deaths. Identification of immunological epitopes on the virus would be highly useful for the development of diagnostic tools and vaccines that will be critical to limiting further spread of COVID-19. Methods To find disease-specific B-cell epitopes that correspond to or mimic natural epitopes, we used phage display technology to determine the targets of specific antibodies present in the sera of immune-responsive COVID-19 patients. Enzyme-linked immunosorbent assays were further applied to assess competitive antibody binding and serological detection. VaxiJen, BepiPred-2.0 and DiscoTope 2.0 were utilized for B-cell epitope prediction. PyMOL was used for protein structural analysis. Results 36 enriched peptides were identified by biopanning with antibodies from two COVID-19 patients; the peptides 4 motifs with consensus residues corresponding to two potential B-cell epitopes on SARS-CoV-2 viral proteins. The putative epitopes and hit peptides were then synthesized for validation by competitive antibody binding and serological detection. Conclusions The identified B-cell epitopes on SARS-CoV-2 may aid investigations into COVID-19 pathogenesis and facilitate the development of epitope-based serological diagnostics and vaccines.

scholarly journals Identification of four linear B-cell epitopes on the SARS-CoV-2 spike protein able to elicit neutralizing antibodiesIdentification of four linear B-cell epitopes on the SARS-CoV-2 spike protein able to elicit neutralizing antibodies

2021 ◽  
Author(s):  
Lin Li ◽  
Zhongpeng Zhao ◽  
Xiaolan Yang ◽  
Wendong Li ◽  
Shaolong Chen ◽  
...  
Keyword(s):  
B Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Epitope ◽  
Spike Protein ◽  
Effective Vaccine ◽  
B Cell Epitopes ◽  
S Protein ◽  
B Cell Epitope ◽  
Linear B

Abstract SARS-CoV-2 unprecedentedly threatens the public health at worldwide level. There is an urgent need to develop an effective vaccine within a highly accelerated time. Here, we present the most comprehensive S-protein-based linear B-cell epitope candidate list by combining epitopes predicted by eight widely-used immune-informatics methods with the epitopes curated from literature published between Feb 6, 2020 and July 10, 2020. We find four top prioritized linear B-cell epitopes in the hotspot regions of S protein can specifically bind with pooled serum antibodies from horses, mice, and monkeys inoculated with different SARS-CoV-2 vaccine candidates or five patients recovering from COVID-19. The four linear B-cell epitopes can induce neutralizing antibodies against both pseudo and live SARS-CoV-2 virus in immunized wild-type BALB/c mice. This study suggests that the four linear B-cell epitopes are potentially important candidates for serological assay or vaccine development.

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