Serological diagnostic kit of SARS-CoV-2 antibodies using CHO-expressed full-length SARS-CoV-2 S1 proteins

  1. Rongqing Zhao
  2. Maohua Li
  3. Hao Song
  4. Jianxin Chen
  5. Wenlin Ren
  6. Yingmei Feng
  7. Jinwen Song
  8. Ya Peng
  9. Bin Su
  10. Xianghua Guo
  11. Yanjun Wang
  12. Jingong Chen
  13. Jianli Li
  14. Hunter Sun
  15. Zhonghu Bai
  16. WenJing Cao
  17. Jin Zhu
  18. Qinlu Zhang
  19. Yufei Sun
  20. Sean Sun
  21. Xinkun Mao
  22. Junchi Su
  23. Hui Chen
  24. Ailiang He
  25. Ronghua Jin
  26. Le Sun

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Abstract

WHO has declared COVID-19 a pandemic with more than 300,000 confirmed cases and more than 14,000 deaths. There is urgent need for accurate and rapid diagnostic kits. Here we report the development and validation of a COVID-19/SARS-CoV-2 S1 serology ELISA kit for the detection of total anti-virus antibody (IgG+IgM) titers in sera from either the general population or patients suspected to be infected. For indirect ELISA, CHO-expressed recombinant full length SARS-CoV-2-S1 protein with 6* His tag was used as the coating antigen to capture the SARS-CoV-2-S1 antibodies specifically. The specificity of the ELISA kit was determined to be 97.5%, as examined against total 412 normal human sera including 257 samples collected prior to the outbreak and 155 collected during the outbreak. The sensitivity of the ELISA kit was determined to be 97.5% by testing against 69 samples from hospitalized and/or recovered COVID-19 patients. The overall accuracy rate reached 97.3%. Most importantly, in one case study, the ELISA test kit was able to identify an infected person who had previously been quarantined for 14 days after coming into contact with a confirmed COVID-19 patient, and discharged after testing negative twice by nucleic acid test. With the assays developed here, we can screen millions of medical staffs in the hospitals and people in residential complex, schools, public transportations, and business parks in the epidemic centers of the outbreaks to fish out the “innocent viral spreaders”, and help to stop the further spreading of the virus.

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  1. ScreenIT

    SciScore for 10.1101/2020.03.26.20042184: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIACUC: Serum samples for assay: The protocols were approved by the institutional ethical committee of Beijing You An Hospital, Capital Medical University.
    Consent: Informed consent was obtained from all the human subjects who participated in the study after the nature and possible consequences of this study had been fully explained and the protocols were approved by the institutional ethical committee.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Experimental Models: Cell Lines
    SentencesResources
    HEK 293F cells and CHO cells and culture media were provided by Zhenge Biotech.,
    HEK 293F
    suggested: RRID:CVCL_6642)
    CHO
    suggested: CLS Cat# 603479/p746_CHO, RRID:CVCL_0213)
    Software and Algorithms
    SentencesResources
    Protein expression and purification: The full length SRARS-CoV-2 S1 gene (GenBank: QIC53204.1) with C terminal were synthesized by GENEWIZ, China, and inserted into mammalian cell expression vectors with either 6* His tag or fused with human IgG Fc.
    GENEWIZ
    suggested: (GENEWIZ, RRID:SCR_003177)

    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.

  2. Version published to 10.1101/2020.03.26.20042184v1 on medRxiv