Nucleocapsid-specific humoral responses improve the control of SARS-CoV-2

  1. Tanushree Dangi
  2. Sarah Sanchez
  3. Mincheol Park
  4. Jacob Class
  5. Michelle Richner
  6. Justin M. Richner
  7. Pablo Penaloza-MacMaster

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Abstract

The spike protein of SARS-CoV-2 is a critical antigen present in all approved SARS-CoV-2 vaccines. This surface viral protein is also the target for all monoclonal antibody therapies, but it is unclear whether antibodies targeting other viral proteins can also improve protection against COVID-19. Here, we interrogate whether nucleocapsid-specific antibodies can improve protection against SARS-CoV-2. We first immunized mice with a nucleocapsid-based vaccine, and then transferred sera from these mice into naïve mice. On the next day, the recipient mice were challenged intranasally with SARS-CoV-2 to evaluate whether nucleocapsid-specific humoral responses affect viral control. Interestingly, mice that received nucleocapsid-specific sera exhibited enhanced control of a SARS-CoV-2 infection. These findings provide the first demonstration that humoral responses specific to an internal coronavirus protein can help clear infection, warranting the inclusion of other viral antigens in next-generation SARS-CoV-2 vaccines and providing a rationale for the clinical evaluation of nucleocapsid-specific monoclonals to treat COVID-19.

Highlights

A SARS-CoV-2 nucleocapsid vaccine elicits robust nucleocapsid-specific antibody responses.

This nucleocapsid vaccine generates memory B cells (MBC).

Nucleocapsid-specific humoral responses do not prevent SARS-CoV-2 infection.

Nucleocapsid-specific humoral responses help control a SARS-CoV-2 infection.

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  1. ScreenIT

    SciScore for 10.1101/2022.03.09.483635: (What is this?)

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

    Table 1: Rigor

    EthicsIACUC: All procedures were performed with the approval of the center for comparative medicine at Northwestern University and the UIC IACUC.
    Sex as a biological variableAdult mice, approximately half females and half males were used for the immunogenicity experiments included in this study.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line AuthenticationAuthentication: Cells were not authenticated as they were purchased from a reputable vendor and certificate of analysis was obtained.

    Table 2: Resources

    Antibodies
    SentencesResources
    Cells were stained with fluorescently-labeled antibodies against CD8α (53-6.7 on PerCP-Cy5.5), CD44 (IM7 on Pacific Blue), and KbN219 (PE).
    CD8α
    suggested: None
    CD44
    suggested: None
    SARS-CoV-2 nucleocapsid specific ELISA: Binding antibody titers were quantified using ELISA as described previously (Dangi et al., 2020; Palacio et al., 2020), using nucleocapsid protein as coating antigens.
    using nucleocapsid protein as coating antigens.
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Vero E6 cells were used to propagate SARS CoV-2 isolate USA-WA1/2020 (BEI resources, NR-52281).
    Vero E6
    suggested: None
    The Ad5 vector was propagated on trans-complementing HEK293 cells (ATCC), purified by cesium chloride density gradient centrifugation, titrated, and then frozen at −80□°C.
    HEK293
    suggested: CLS Cat# 300192/p777_HEK293, RRID:CVCL_0045)
    In brief, Vero cells were passaged in DMEM with 10%
    Vero
    suggested: None
    Viral titers were determined by plaque assay on Vero-E6 cells.
    Vero-E6
    suggested: None
    Experimental Models: Organisms/Strains
    SentencesResources
    K18-hACE2 mice were anesthetized with isoflurane and challenged with 103 PFU of SARS-CoV-2 intranasally.
    K18-hACE2
    suggested: RRID:IMSR_GPT:T037657)
    Software and Algorithms
    SentencesResources
    Flow cytometry samples were acquired with a Becton Dickinson Canto II or an LSRII and analyzed using FlowJo v10 (Treestar).
    FlowJo
    suggested: (FlowJo, RRID:SCR_008520)
    Data were analyzed using Prism (Graphpad).
    Prism
    suggested: (PRISM, RRID:SCR_005375)
    Graphpad
    suggested: (GraphPad, RRID:SCR_000306)

    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: We detected the following sentences addressing limitations in the study:
    A limitation of our study is that we only performed adoptive sera transfers early after nucleocapsid vaccination. It is unknown if a similar level of protection would be observed if the passive immunizations were performed using sera from later time points post-vaccination. We detected memory B cells, suggesting that the nucleocapsid-specific antibody response was long-lived, but future studies are needed to evaluate the durability of nucleocapsid-specific antibody responses and the mechanisms by which they clear SARS-CoV-2 infection. Overall, we show that passive immunization using nucleocapsid-specific sera improves the control of a SARS-CoV-2 infection. These data provide insights for next-generation vaccines and for expanding the armamentarium of antibody-based therapies for COVID-19.

    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.
    • No funding statement was detected.
    • No protocol registration statement was detected.

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

    About SciScore

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  2. Version published to 10.1101/2022.03.09.483635v1 on bioRxiv