A mRNA vaccine encoding for a RBD 60-mer nanoparticle elicits neutralizing antibodies and protective immunity against the SARS-CoV-2 delta variant in transgenic K18-hACE2 mice

  1. Pascal Brandys
  2. Xavier Montagutelli
  3. Irena Merenkova
  4. Güliz T Barut
  5. Volker Thiel
  6. Nicholas J Schork
  7. Bettina Trüeb
  8. Laurine Conquet
  9. Aihua Deng
  10. Aleksandar Antanasijevic
  11. Hyun-Ku Lee
  12. Martine Valière
  13. Anoop Sindhu
  14. Gita Singh
  15. Jens Herold

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Abstract

Two years into the COVID-19 pandemic there is still a need for vaccines to effectively control the spread of novel SARS-CoV-2 variants and associated cases of severe disease. Here we report a messenger RNA vaccine directly encoding for a nanoparticle displaying 60 receptor binding domains (RBDs) of SARS-CoV-2 that acts as a highly effective antigen. A construct encoding the RBD of the delta variant elicits robust neutralizing antibody response with neutralizing titers an order of magnitude above currently approved mRNA vaccines. The construct also provides protective immunity against the delta variant in a widely used transgenic mouse model. We ultimately find that the proposed mRNA RBD nanoparticle-based vaccine provides a flexible platform for rapid development and will likely be of great value in combatting current and future SARS-CoV-2 variants of concern.

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  1. ScreenIT

    SciScore for 10.1101/2022.03.21.485224: (What is this?)

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

    Table 1: Rigor

    EthicsIACUC: The studies design and animal usage were reviewed and approved by the Institutional Animal Care and Use Committee under numbers 20-024, 21-006, 21-020 and 21-029 for compliance with regulations prior to study initiation.
    Field Sample Permit: Experimental protocols were approved by the Institut Pasteur Ethics Committee under number dap210050 and authorized by the French Ministry of Research under number 31816.
    IRB: Experimental protocols were approved by the Institut Pasteur Ethics Committee under number dap210050 and authorized by the French Ministry of Research under number 31816.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The membrane was incubated with a polyclonal anti-RBD antibody (Sino Biological: 40592-T62) at 1:2000 dilution followed by incubation with HRP conjugated anti-rabbit polyclonal antibody and reaction was detected by chemiluminescence and revealed the expressed protein at the estimated size of the RBD-NP.
    anti-RBD
    suggested: None
    anti-rabbit
    suggested: None
    The absorbance of the sample was inversely dependent on the titer of the anti-SARS-CoV-2 neutralizing antibodies.
    anti-SARS-CoV-2 neutralizing antibodies .
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Transcribed capped mRNA was electroporated into baby hamster kidney (BHK-21) cells expressing SARS-CoV-2 N protein.
    BHK-21
    suggested: ATCC Cat# CRL-6281, RRID:CVCL_1914)
    Subsequently, progeny virus was used to infect fresh VeroE6-TMPRSS2 cells to generate P.1 stocks for downstream experiments.
    VeroE6-TMPRSS2
    suggested: JCRB Cat# JCRB1819, RRID:CVCL_YQ49)
    SARS-CoV-2 delta neutralization assay: Vero-E6 cells were seeded at a density of 1.5x104 cells/100μl per well (in DMEM supplemented with 10% FBS, 1% non-essential amino acids (NEAA) and 1% Penicillin-Streptomycin) in 96-well cell culture plates one day before and incubated over night at 37°C, 5% CO2.
    Vero-E6
    suggested: None
    Subsequently 100 μl of serum and virus mixtures were added on confluent Vero E6 cells and 96-well plates were incubated for 72 h at 37°C.
    Vero E6
    suggested: RRID:CVCL_XD71)
    Experimental Models: Organisms/Strains
    SentencesResources
    Mice: CB6F1/J mice and B6.Cg-Tg(K18-ACE2)2Prlmn/J transgenic mice were purchased from The Jackson Laboratory (SN 100007 and 034860, respectively) under a license agreement.
    CB6F1/J
    suggested: RRID:IMSR_JAX:100007)
    B6.Cg-Tg(K18-ACE2)2Prlmn/J
    suggested: RRID:IMSR_JAX:034860)
    Recombinant DNA
    SentencesResources
    Transient expression of RBD-NP protein: FreeStyle 293 cells (2.106) in 500 ml of SFM media were transfected using 600 μg of pHL-sec plasmid DNA containing RBD-NP cDNA for transient expression of glycosylated RBD-NP according to the manufacturer’s protocol (Life Technology).
    pHL-sec
    suggested: RRID:Addgene_99845)
    The supercoiled pUC19 DNA was upscaled, linearized with BsmBI, and purified.
    pUC19
    suggested: RRID:Addgene_50005)
    Software and Algorithms
    SentencesResources
    Statistical analysis: Statistical analyses were performed using Prism v9.3.1 (GraphPad Software) (Fig. 2-3, 5, 10-11) or using R Statistical Software v4.1.2
    Prism
    suggested: (PRISM, RRID:SCR_005375)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)
    R Statistical
    suggested: (R Project for Statistical Computing, RRID:SCR_001905)

    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
    NCT04742738Active, not recruitingSafety and Immunogenicity Study of SARS-CoV-2 Nanoparticle V…
    NCT04750343Active, not recruitingSafety and Immunogenicity Study of SARS-CoV-2 Nanoparticle V…
    NCT05175950Not yet recruitingSafety, Reactogenicity, and Immunogenicity Study of Heterolo…
    NCT04523571CompletedSafety and Immunogenicity of SARS-CoV-2 mRNA Vaccine (BNT162…

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

    Results from JetFighter: We did not find any issues relating to colormaps.

    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.
    • No protocol registration statement was detected.

    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.

  2. Version published to 10.1101/2022.03.21.485224v1 on bioRxiv