SARS-CoV-2 Epitope Mapping on Microarrays Highlights Strong Immune-Response to N Protein Region

  1. Angelo Musicò
  2. Roberto Frigerio
  3. Alessandro Mussida
  4. Luisa Barzon
  5. Alessandro Sinigaglia
  6. Silvia Riccetti
  7. Federico Gobbi
  8. Chiara Piubelli
  9. Greta Bergamaschi
  10. Marcella Chiari
  11. Alessandro Gori
  12. Marina Cretich

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Abstract

A workflow for rapid SARS-CoV-2 epitope discovery on peptide microarrays is herein reported. The process started with a proteome-wide screening of immunoreactivity based on the use of a high-density microarray followed by a refinement and validation phase on a restricted panel of probes using microarrays with tailored peptide immobilization through a click-based strategy. Progressively larger, independent cohorts of Covid-19 positive sera were tested in the refinement processes, leading to the identification of immunodominant regions on SARS-CoV-2 spike (S), nucleocapsid (N) protein and Orf1ab polyprotein. A summary study testing 50 serum samples highlighted an epitope of the N protein (region 155–71) providing good diagnostic performance in discriminating Covid-19 positive vs. healthy individuals. Using this epitope, 92% sensitivity and 100% specificity were reached for IgG detection in Covid-19 samples, and no cross-reactivity with common cold coronaviruses was detected. Likewise, IgM immunoreactivity in samples collected within the first month after symptoms onset showed discrimination ability. Overall, epitope 155–171 from N protein represents a promising candidate for further development and rapid implementation in serological tests.

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  1. Version published to 10.3390/vaccines9010035
  2. ScreenIT

    SciScore for 10.1101/2020.11.09.374082: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: The study was approved by the ethic committee of IRCCS Sacro Cuore Don Calabria Hospital and study subjects provided written informed consent.
    Consent: The study was approved by the ethic committee of IRCCS Sacro Cuore Don Calabria Hospital and study subjects provided written informed consent.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The second incubation were performed with secondary antibody (Anti-Human IgG-Cy3, Jackson ImmunoReserarch; Anti-Human IgM-Cy5, Invitrogen) diluted in ratio 1:1000 in incubation buffer with 1% BSA.
    Anti-Human IgG-Cy3
    suggested: None
    Anti-Human IgM-Cy5
    suggested: None

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

    About SciScore

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  3. Version published to 10.1101/2020.11.09.374082v1 on bioRxiv