Monoclonal antibodies for the S2 subunit of spike of SARS-CoV-1 cross-react with the newly-emerged SARS-CoV-2

  1. Zhiqiang Zheng
  2. Vanessa Marthe Monteil
  3. Sebastian Maurer-Stroh
  4. Chow Wenn Yew
  5. Carol Leong
  6. Nur Khairiah Mohd-Ismail
  7. Suganya Cheyyatraivendran Arularasu
  8. Vincent Tak Kwong Chow
  9. Raymond Tzer Pin Lin
  10. Ali Mirazimi
  11. Wanjin Hong
  12. Yee-Joo Tan

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Abstract

A novel coronavirus, SARS-CoV-2, which emerged at the end of 2019 and causes COVID-19, has resulted in worldwide human infections. While genetically distinct, SARS-CoV-1, the aetiological agent responsible for an outbreak of severe acute respiratory syndrome (SARS) in 2002–2003, utilises the same host cell receptor as SARS-CoV-2 for entry: angiotensin-converting enzyme 2 (ACE2). Parts of the SARS-CoV-1 spike glycoprotein (S protein), which interacts with ACE2, appear conserved in SARS-CoV-2.

Aim

The cross-reactivity with SARS-CoV-2 of monoclonal antibodies (mAbs) previously generated against the S protein of SARS-CoV-1 was assessed.

Methods

The SARS-CoV-2 S protein sequence was aligned to those of SARS-CoV-1, Middle East respiratory syndrome (MERS) and common-cold coronaviruses. Abilities of mAbs generated against SARS-CoV-1 S protein to bind SARS-CoV-2 or its S protein were tested with SARS-CoV-2 infected cells as well as cells expressing either the full length protein or a fragment of its S2 subunit. Quantitative ELISA was also performed to compare binding of mAbs to recombinant S protein.

Results

An immunogenic domain in the S2 subunit of SARS-CoV-1 S protein is highly conserved in SARS-CoV-2 but not in MERS and human common-cold coronaviruses. Four murine mAbs raised against this immunogenic fragment could recognise SARS-CoV-2 S protein expressed in mammalian cell lines. In particular, mAb 1A9 was demonstrated to detect S protein in SARS-CoV-2-infected cells and is suitable for use in a sandwich ELISA format.

Conclusion

The cross-reactive mAbs may serve as useful tools for SARS-CoV-2 research and for the development of diagnostic assays for COVID-19.

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  1. Version published to 10.2807/1560-7917.es.2020.25.28.2000291
  2. ScreenIT

    SciScore for 10.1101/2020.03.06.980037: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Cells were immunolabelled for 1 hour at RT with the indicated murine mAb and 45 min with Alexa Fluor 488-conjugated goat anti-mouse IgG antibody (Life Technologies).
    anti-mouse IgG
    suggested: None
    They were then washed 3 times with PBS and incubated with goat anti-mouse conjugated to Alexa Fluor 488-conjugated goat anti-mouse IgG antibody (Thermo Fisher) containing DAPI in immunofluorescence buffer for an additional incubation of 30 minutes.
    anti-mouse
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Cells: Vero E6 and COS-7 cells were purchased from American Type Culture Collection (Manassas, VA, USA) and cultured in Dulbecco’s Modified Eagle’s Medium (DMEM; Thermo Scientific) supplemented with 10% foetal bovine serum (FBS; HyClone) and penicillin-streptomycin solution (Thermo Fisher Scientific).
    Vero E6
    suggested: None
    COS-7
    suggested: None
    Vero-E6 cells were infected with SARS-CoV-2 (SARS-CoV-2-Iso/01/human/2020/SWE, GenBank accession no. MT093571) at a multiplicity of infection (MOI) of 1 in DMEM 2% FBS (Thermo Fisher).
    Vero-E6
    suggested: None
    Software and Algorithms
    SentencesResources
    A multiple sequence alignment was created with MAFFT using the slow but accurate L-INS-I parameter settings [21] and the alignment curated, cut to the target region 1029-1192 (SARS-CoV numbering) and visualized with Jalview [22].
    MAFFT
    suggested: (MAFFT, RRID:SCR_011811)
    Jalview
    suggested: (Jalview, RRID:SCR_006459)
    The nucleotide sequences were searched with BLASTX against the reference spike glycoprotein.
    BLASTX
    suggested: (BLASTX, RRID:SCR_001653)

    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.

    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 10.1101/2020.03.06.980037v1 on bioRxiv