Evidence of SARS-CoV-2-Specific Memory B Cells Six Months After Vaccination With the BNT162b2 mRNA Vaccine

  1. Annalisa Ciabattini
  2. Gabiria Pastore
  3. Fabio Fiorino
  4. Jacopo Polvere
  5. Simone Lucchesi
  6. Elena Pettini
  7. Stefano Auddino
  8. Ilaria Rancan
  9. Miriam Durante
  10. Michele Miscia
  11. Barbara Rossetti
  12. Massimiliano Fabbiani
  13. Francesca Montagnani
  14. Donata Medaglini

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Abstract

SARS-CoV-2 mRNA vaccines have demonstrated high efficacy and immunogenicity, but limited information is currently available on memory B cell generation and long-term persistence. Here, we investigated spike-specific memory B cells and humoral responses in 145 subjects, up to 6 months after the BNT162b2 vaccine (Comirnaty) administration. Spike-specific antibodies peaked 7 days after the second dose and significant antibody titers and ACE2/RBD binding inhibiting activity were still observed after 6 months, despite a progressive decline over time. Concomitant to antibody reduction, spike-specific memory B cells, mostly IgG class-switched, increased in the blood of vaccinees and persisted 6 months after vaccination. Following the in vitro restimulation, circulating memory B cells reactivated and produced spike-specific antibodies. A high frequency of spike-specific IgG + plasmablasts, identified by computational analysis 7 days after boost, positively correlated with the generation of IgG + memory B cells at 6 months. These data demonstrate that mRNA BNT162b2 vaccine elicits strong B cell immunity with spike-specific memory B cells that still persist 6 months after vaccination, playing a crucial role for a rapid response to SARS-CoV-2 virus encounter.

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  1. Version published to 10.3389/fimmu.2021.740708
  2. ScreenIT

    SciScore for 10.1101/2021.07.12.21259864: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: All participants provided written informed consent before participation to the study.
    IRB: The study was performed in compliance with all relevant ethical regulations and the protocol was approved by local Ethical Committee for Clinical experimentation (CEASVE), protocol code IMMUNO_COV.
    Field Sample Permit: Clinical data collection and management were carried out using the software REDCap (Research Electronic Data Capture, Vanderbilt University).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Anti-human horseradish peroxidase (HRP)-conjugated antibodies for IgG (diluted 1:6000), IgM, IgA (diluted 1:4000), IgG1, IgG2, IgG3, IgG4 (diluted 1:2000; all from Southern Biotechnology) were added in diluent buffer for 1 h at RT.
    Anti-human horseradish peroxidase ( HRP)-conjugated antibodies for IgG
    suggested: None
    IgA
    suggested: None
    IgG1
    suggested: None
    IgG2 , IgG3
    suggested: (Abgent Cat# AT2000a, RRID:AB_1551611)
    IgG4
    suggested: None
    Cells were washed and stained for 30 min at 4°C with the following antibody-fluorochrome panel: CD3-PECy 7 (clone SK7); CD56-PECy7 (clone B159), CD14-PECy7 (clone M5E2), CD19-BUV395 (clone SJ25C1), IgM-BV421 (clone G20-127), IgD-PE (clone IA6-2), CD11c-BB700 (clone 3.9), CXCR5-BV650 (clone RF8B2), CD27-APC-R700 (clone M-T271), CD24-BV786 (clone ML5), CD38-BUV737 (clone HB7), IgG-BV711 (clone G18-145), CD138-PE-CF594 (clone MI15) (all from Becton Dickinson),
    CD14-PECy7
    suggested: None
    CD19-BUV395
    suggested: None
    IgM-BV421
    suggested: None
    IgD-PE
    suggested: (SouthernBiotech Cat# 1120-09L, RRID:AB_2794610)
    CD11c-BB700
    suggested: None
    CXCR5-BV650
    suggested: None
    CD27-APC-R700
    suggested: None
    CD24-BV786
    suggested: None
    CD38-BUV737
    suggested: None
    IgG-BV711
    suggested: None
    CD138-PE-CF594
    suggested: None
    Multiscreen filter 96 well plates were pre-wetted with 70% ethanol and then coated with recombinant wild type SARS-CoV-2 Spike S1+S2 ECD (Sino Biological, 10 μg/ml) for the detection of antigen-specific IgG or with anti-Ig capture antibody for the detection of total IgG and IgM overnight at 4 °C.
    antigen-specific IgG
    suggested: None
    anti-Ig
    suggested: None
    Software and Algorithms
    SentencesResources
    Clinical data collection and management were carried out using the software REDCap (Research Electronic Data Capture, Vanderbilt University).
    REDCap
    suggested: (REDCap, RRID:SCR_003445)
    Computational flow cytometry analysis: The B cell population analyzed in our data set was gated as live, singlet, CD3−/CD14-/CD56- CD19+ Spike+ cells using FlowJo v10 (TreeStar, USA).
    FlowJo
    suggested: (FlowJo, RRID:SCR_008520)
    Flow cytometry standard (FCS) files were exported as uncompensated data in R environment as flowSet object (list of FCS), that was then compensated with FlowCore package 2.0.1 (29) and logicle transformed (30) using the estimateLogicle function for automatic parameters selection for each fluorescence marker.
    FlowCore
    suggested: (flowCore, RRID:SCR_002205)
    The Euclidean distance was used in both the FlowSOM clustering and metaclustering.
    FlowSOM
    suggested: (FlowSOM, RRID:SCR_016899)
    Thresholds to bisect positive and negative cells for each marker expression were automatically set with flowDensity package (31).
    flowDensity
    suggested: None
    Analyses were performed using GraphPad Prism v9 (GraphPad Software, USA) All data are available in the main text or the supplementary materials.
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04368728RecruitingStudy to Describe the Safety, Tolerability, Immunogenicity, …

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: Please consider improving the rainbow (“jet”) colormap(s) used on page 27. At least one figure is not accessible to readers with colorblindness and/or is not true to the data, i.e. not perceptually uniform.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a protocol registration statement.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2021.07.12.21259864v1 on medRxiv