Convalescent plasma therapy for the treatment of patients with COVID‐19: Assessment of methods available for antibody detection and their correlation with neutralising antibody levels

  1. Heli Harvala
  2. Matthew L. Robb
  3. Nick Watkins
  4. Samreen Ijaz
  5. Steven Dicks
  6. Monika Patel
  7. Piyada Supasa
  8. Dejnirattisai Wanwisa
  9. Chang Liu
  10. Juthathip Mongkolsapaya
  11. Abbie Bown
  12. Daniel Bailey
  13. Richard Vipond
  14. Nicholas Grayson
  15. Nigel Temperton
  16. Sunetra Gupta
  17. Rutger J. Ploeg
  18. Jai Bolton
  19. Alex Fyfe
  20. Robin Gopal
  21. Peter Simmonds
  22. Gavin Screaton
  23. Craig Thompson
  24. Tim Brooks
  25. Maria Zambon
  26. Gail Miflin
  27. David J. Roberts

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Abstract

Introduction

The lack of approved specific therapeutic agents to treat coronavirus disease (COVID‐19) associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection has led to the rapid implementation of convalescent plasma therapy (CPT) trials in many countries, including the United Kingdom. Effective CPT is likely to require high titres of neutralising antibody (nAb) in convalescent donations. Understanding the relationship between functional neutralising antibodies and antibody levels to specific SARS‐CoV‐2 proteins in scalable assays will be crucial for the success of a large‐scale collection. We assessed whether neutralising antibody titres correlated with reactivity in a range of enzyme‐linked immunosorbent assays (ELISA) targeting the spike (S) protein, the main target for human immune response.

Methods

Blood samples were collected from 52 individuals with a previous laboratory‐confirmed SARS‐CoV‐2 infection. These were assayed for SARS‐CoV‐2 nAbs by microneutralisation and pseudo‐type assays and for antibodies by four different ELISAs. Receiver operating characteristic (ROC) analysis was used to further identify sensitivity and specificity of selected assays to identify samples containing high nAb levels.

Results

All samples contained SARS‐CoV‐2 antibodies, whereas neutralising antibody titres of greater than 1:20 were detected in 43 samples (83% of those tested) and >1:100 in 22 samples (42%). The best correlations were observed with EUROimmun immunoglobulin G (IgG) reactivity (Spearman Rho correlation coefficient 0.88; p  < 0.001). Based on ROC analysis, EUROimmun would detect 60% of samples with titres of >1:100 with 100% specificity using a reactivity index of 9.1 (13/22).

Discussion

Robust associations between nAb titres and reactivity in several ELISA‐based antibody tests demonstrate their possible utility for scaled‐up production of convalescent plasma containing potentially therapeutic levels of anti‐SARS‐CoV‐2 nAbs.

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  1. Version published to 10.1111/tme.12746
  2. ScreenIT

    SciScore for 10.1101/2020.05.20.20091694: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Consent is collected using NHS Blood and Transplant approved consent forms and these follow Blood Safety and Quality Regulations enforced by the Medicines & Healthcare products Regulatory Agency.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Ethical statement: Signed donor consent is collected from each donor at the time of donation, including convalescent plasma donors and covers all the testing including anti-SARS-CoV-2 antibody testing.
    anti-SARS-CoV-2
    suggested: None
    Enzyme-linked trimeric spike immunosorbent assay (ELISA - Oxford): Antibodies to the trimeric spike (S; based on YP009724390.1) protein were detected by ELISA as previously described, using 2% skimmed milk in PBS as a blocking agent and ALP-conjugated anti-human IgG (A95455; Sigma) at 1:10,000 dilution12.
    anti-human IgG
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Briefly, virus was incubated with a serial dilution of convalescent plasma obtained from recovered patients, after which a suspension of Vero E6 cells were added.
    Vero E6
    suggested: RRID:CVCL_XD71)

    Results from OddPub: Thank you for sharing your data.

    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 10.1101/2020.05.20.20091694 on medRxiv