Evaluation of a novel multiplexed assay for determining IgG levels and functional activity to SARS-CoV-2

  1. Marina Johnson
  2. Helen R. Wagstaffe
  3. Kimberly C. Gilmour
  4. Annabelle Lea Mai
  5. Joanna Lewis
  6. Adam Hunt
  7. Jake Sirr
  8. Christopher Bengt
  9. Louis Grandjean
  10. David Goldblatt

Reviewed by

Read the full article See related articles

Discuss this preprint

Start a discussion What are Sciety discussions?

Listed in

Log in to save this article

Abstract

Background

The emergence of SARS-CoV-2 has led to the development of new serological assays that could aid in diagnosis and evaluation of seroprevalence to inform an understanding of the burden of COVID-19 disease. Many available tests lack rigorous evaluation and therefore results may be misleading.

Objectives

The aim of this study was to assess the performance of a novel multiplexed immunoassay for the simultaneous detection of antibodies against SARS-CoV-2 trimeric spike (S), spike receptor binding domain (RBD), spike N terminal domain and nucleocapsid antigen and a novel pseudo-neutralisation assay.

Methods

A multiplexed solid-phase chemiluminescence assay (Meso Scale Discovery) was evaluated for the simultaneous detection of IgG binding to four SARS-CoV-2 antigens and the quantification of antibody-induced ACE-2 binding inhibition (pseudo-neutralisation assay). Sensitivity was evaluated with a total of 196 COVID-19 serum samples (169 confirmed PCR positive and 27 anti-nucleocapsid IgG positive) from individuals with mild symptomatic or asymptomatic disease. Specificity was evaluated with 194 control serum samples collected from adults prior to December 2019.

Results

The specificity and sensitivity of the binding IgG assay was highest for S protein with a specificity of 97.4% and sensitivity of 96.2% for samples taken 14 days and 97.9% for samples taken 21 days following the onset of symptoms. IgG concentration to S and RBD correlated strongly with percentage inhibition measured by the pseudo-neutralisation assay.

Conclusion

Excellent sensitivity for IgG detection was obtained over 14 days since onset of symptoms for three SARS-CoV-2 antigens (S, RBD and N) in this multiplexed assay which can also measure antibody functionality.

Article activity feed

  1. ScreenIT

    SciScore for 10.1101/2020.07.20.213249: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Serum Samples: Serum samples for sensitivity analyses were obtained from Great Ormond Street Children’s Hospital NHS Foundation Trust (GOSH) and came from three sources; (i) healthcare workers who tested SARS-CoV-2 RT-PCR positive following signs or symptoms of COVID-19 and who gave written consent for participation in the service evaluation of SARS-CoV-2 serological assays, (ii) staff enrolling in a prospective longitudinal cohort study of SARS-CoV-Serology (COSTARS, IRAS 282713, ClinicalTrials.gov Identifier: NCT04380896) who tested positive in a commercial screening assay for anti-Nucleocapsid IgG (Epitope Diagnostics Inc, San Diego, USA) (iii) a small number of RT-PCR positive sera from hospitalised children (
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    This serum was calibrated against research reagents NIBSC 20/130 and NIBSC 20/124 distributed by the National Institute for Standards and Biological Control (NIBSC, Potters Bar, UK, https://www.nibsc.org/) for the purpose of development and evaluation of serological assays for the detection of antibodies against SARS-CoV-2.
    SARS-CoV-2
    suggested: None
    After incubation for 2 hours with shaking at 700rpm, the plates were washed three times and detection antibody was added at 2 µg/mL (MSD SULFO-TAG™ Anti-Human IgG Antibody).
    Anti-Human IgG
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistical analysis: Statistical analysis was performed using MSD Discovery Workbench and GraphPad Prism version 8.0 (GraphPad, San Diego, CA)
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    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: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04380896RecruitingCOVID-19 Staff Testing of Antibody Responses Study (Co-Stars…

    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

    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 10.1101/2020.07.20.213249 on bioRxiv