Weak correlation between antibody titers and neutralizing activity in sera from SARS‐CoV‐2 infected subjects

  1. Elena Criscuolo
  2. Roberta A. Diotti
  3. Marta Strollo
  4. Serena Rolla
  5. Alessandro Ambrosi
  6. Massimo Locatelli
  7. Roberto Burioni
  8. Nicasio Mancini
  9. Massimo Clementi
  10. Nicola Clementi

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Abstract

Plenty of serologic tests for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) have been developed so far, thus documenting the importance of evaluating the relevant features of the immune response to this viral agent. The performance of these assays is currently under investigation. Amongst them, LIAISON® SARS‐CoV‐2 S1/S2 IgG by DiaSorin and Elecsys Anti‐SARS‐CoV‐2 cobas® by Roche are currently used by laboratory medicine hospital departments in Italy and many other countries. In the present study, we firstly compared two serologic tests on serum samples collected at two different time points from 46 laboratory‐confirmed coronavirus disease‐2019 (COVID‐19) subjects. Secondly, 85 negative serum samples collected before the SARS‐CoV‐2 pandemic were analyzed. Thirdly, possible correlations between antibody levels and the resulting neutralizing activity against a clinical isolate of SARS‐CoV‐2 were evaluated. Results revealed that both tests are endowed with low sensitivity on the day of hospital admission, which increased to 97.8% and 100% for samples collected after 15 days for DiaSorin and Roche tests, respectively. The specificity evaluated for the two tests ranges from 96.5% to 100%, respectively. Importantly, a poor direct correlation between antibody titers and neutralizing activity levels was evidenced in the present study. These data further shed light on both potentials and possible limitations related to SARS‐CoV‐2 serology. In this context, great efforts are still necessary for investigating antibody kinetics to develop novel diagnostic algorithms. Moreover, further investigations on the role of neutralizing antibodies and their correlate of protection will be of paramount importance for the development of effective vaccines.

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  1. Version published to 10.1002/jmv.26605
  2. ScreenIT

    SciScore for 10.1101/2020.07.10.20150375: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    RandomizationForty-six serum samples were randomly collected from laboratory-confirmed symptomatic COVID-19 patients on their admission to the hospital (T0) and 15 days later (T15).
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    SARS-CoV-2 S1/S2 IgG assay by DiaSorin were used for detecting anti-SARS-CoV-2 antibodies in all serum samples.
    anti-SARS-CoV-2
    suggested: None
    The electrochemiluminescence immunoassay (ECLIA) can detect the presence of IgG, IgM, and IgA antibodies recognizing the N protein (8).
    IgA
    suggested: None
    The SARS-CoV-2 S1/S2 IgG assay by DiaSorin can detect IgG antibodies directed against two recombinant SARS-CoV-2 proteins: the S1 and S2 which are involved in both docking and fusion processes of the virus (9).
    DiaSorin can detect IgG
    suggested: None
    S2
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Microneutralization experiments: Vero E6 cells were seeded into 96 wells plates 24 h prior to the experiment performed at 95% cell confluency for each well.
    Vero E6
    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: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04318366RecruitingCOVID-19 Patients Characterization, Biobank, Treatment Respo…

    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 10.1101/2020.07.10.20150375v1 on medRxiv