Phage-like particle vaccines are highly immunogenic and protect against pathogenic coronavirus infection and disease

  1. Bennett J. Davenport
  2. Alexis Catala
  3. Stuart M. Weston
  4. Robert M. Johnson
  5. Jeremy Ardanuy
  6. Holly L. Hammond
  7. Carly Dillen
  8. Matthew B. Frieman
  9. Carlos E. Catalano
  10. Thomas E. Morrison

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Abstract

The response by vaccine developers to the COVID-19 pandemic has been extraordinary with effective vaccines authorized for emergency use in the United States within 1 year of the appearance of the first COVID-19 cases. However, the emergence of SARS-CoV-2 variants and obstacles with the global rollout of new vaccines highlight the need for platforms that are amenable to rapid tuning and stable formulation to facilitate the logistics of vaccine delivery worldwide. We developed a “designer nanoparticle” platform using phage-like particles (PLPs) derived from bacteriophage lambda for a multivalent display of antigens in rigorously defined ratios. Here, we engineered PLPs that display the receptor-binding domain (RBD) protein from SARS-CoV-2 and MERS-CoV, alone (RBD SARS -PLPs and RBD MERS -PLPs) and in combination (hCoV-RBD PLPs). Functionalized particles possess physiochemical properties compatible with pharmaceutical standards and retain antigenicity. Following primary immunization, BALB/c mice immunized with RBD SARS - or RBD MERS -PLPs display serum RBD-specific IgG endpoint and live virus neutralization titers that, in the case of SARS-CoV-2, were comparable to those detected in convalescent plasma from infected patients. Further, these antibody levels remain elevated up to 6 months post-prime. In dose-response studies, immunization with as little as one microgram of RBD SARS -PLPs elicited robust neutralizing antibody responses. Finally, animals immunized with RBD SARS -PLPs, RBD MERS -PLPs, and hCoV-RBD PLPs were protected against SARS-CoV-2 and/or MERS-CoV lung infection and disease. Collectively, these data suggest that the designer PLP system provides a platform for facile and rapid generation of single and multi-target vaccines.

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  1. Version published to 10.1038/s41541-022-00481-1
  2. ScreenIT

    SciScore for 10.1101/2021.11.08.467648: (What is this?)

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

    Table 1: Rigor

    EthicsIACUC: The protocols were approved by the Institutional Animal Care and Use Committees at the University of Colorado School of Medicine (Assurance Number A3269-01) and the University of Maryland School of Medicine (Assurance number D16-00125 (A3200-01)).
    Sex as a biological variableFemale BALB/c mice were purchased from The Jackson Laboratory. 6-8-week-old mice were immunized with WT PLPs (control), RBDSARS-PLPs, RBDMERS-PLPs, or hCoV-RBD PLPs preparations in 50 μl PBS via i.m. injection in the hind leg.
    Randomizationnot detected.
    BlindingSlides were examined in a blinded fashion for total inflammation, periarteriolar, and peribronchiolar inflammation and epithelial cell denuding.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    ELISA: SARS-CoV-2 and MERS-CoV RBD-specific antibody responses in mouse and human sera were measured by ELISA.
    ELISA
    suggested: None
    SARS-CoV-2
    suggested: None
    Samples were removed, and wells were washed three times with PBS-T and probed with secondary antibodies diluted at 1:4000 in PBS-T; goat anti-mouse IgG-HRP (Southern Biotech, 1030-05)
    anti-mouse IgG-HRP
    suggested: None
    Following blocking and washing, wells were incubated for 1.5 h at room temperature with either chimeric human anti-SARS-CoV spike antibody clone CR3022 (Absolute Antibody, Ab01680) or mouse anti-MERS-CoV spike antibody clone D12 (Absolute Antibody, Ab00696) prepared in a 2-fold dilution series in PBS-T with a starting dilution of 1:200 and signal was developed as described above.
    anti-MERS-CoV
    suggested: None
    Cells were fixed with 1% paraformaldehyde (PFA; Acros Organics, 416780030) and probed with 1 μg/mL of chimeric human anti-SARS-CoV spike antibody (CR3022, Absolute Antibody, Ab01680) in Perm Wash (1X PBS/0.1% saponin/0.1% BSA) for 2 h at room temperature.
    anti-SARS-CoV
    suggested: None
    CR3022
    suggested: (Imported from the IEDB Cat# CR3022, RRID:AB_2848080)
    Experimental Models: Cell Lines
    SentencesResources
    Plaque assay: Vero E6 cells were seeded in 12-well plates one day prior to virus inoculation.
    Vero E6
    suggested: None
    Experimental Models: Organisms/Strains
    SentencesResources
    For virulent virus challenge, mice were anaesthetized by intraperitoneal injection with 50 μL of a mix of xylazine (0.38 mg/mouse) and ketamine hydrochloride (1.3 mg/mouse) diluted in PBS. Immunized BALB/c mice were inoculated intranasally (i.n.) with 104 PFU of SARS-CoV-2 MA10.
    BALB/c
    suggested: None
    Recombinant DNA
    SentencesResources
    Purification of recombinant hCoV RBD proteins: A pCAGGS expression vector encoding the SARS-CoV-2 spike RBD was obtained from Dr. Florian Krammer
    pCAGGS
    suggested: RRID:Addgene_18926)
    A pTwist-CMV expression vector (Twist Biosciences Technology) encoding the MERS-CoV spike RBD was kindly provided by Dr. Peter S. Kim, Stanford University (83).
    pTwist-CMV
    suggested: None
    To quantify SARS-CoV-2 subgenomic RNA, we extrapolated viral RNA levels from a standard curve using defined concentrations of a plasmid containing an amplified SARS-CoV-2 subgenomic fragment (pCR-sgN TOPO).
    pCR-sgN
    suggested: None
    This amplicon was cloned into the pCR4 Blunt TOPO vector (Invitrogen, K2875J10), sequence confirmed, and used in a dilution series of defined gene copies.
    pCR4 Blunt TOPO
    suggested: None
    Software and Algorithms
    SentencesResources
    Images were processed in Fiji (85) and measurements were based on 100 particles with values reported as mean ± standard deviation.
    Fiji
    suggested: (Fiji, RRID:SCR_002285)
    The FRNT50 titers were calculated relative to a virus only control (no serum) set at 100%, using GraphPad Prism 9.1.2 (La Jolla, CA) default nonlinear curve fit constrained between 0 and 100%.
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    Statistical Analysis: Statistical significance was assigned when P values were < 0.05 using Prism Version 9.1.2 (GraphPad).
    Prism
    suggested: (PRISM, RRID:SCR_005375)
    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: No clinical trial numbers were referenced.

    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.

  3. Version published to 10.1101/2021.11.08.467648v1 on bioRxiv