Quantifying Absolute Neutralization Titers against SARS-CoV-2 by a Standardized Virus Neutralization Assay Allows for Cross-Cohort Comparisons of COVID-19 Sera

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Abstract

Vaccines and antibody-based therapeutics like convalescent-phase plasma therapy are premised upon inducing or transferring neutralizing antibodies that inhibit SARS-CoV-2 entry into cells. Virus neutralization assays (VNAs) for measuring neutralizing antibody titers (NATs) are an essential part of determining vaccine or therapeutic efficacy.

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  1. SciScore for 10.1101/2020.08.13.20157222: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Sera acquisition: All patient sera were acquired after approval by the respective institutional review boards and/or equivalent oversight bodies (Bioethics Committee, Independent Ethics Committee) are indicated: (1) Mount Sinai Hospital Institutional Review Board (New York, USA), (2) Louisiana State University Health Sciences Center – Shreveport (LSUHS, Louisiana, USA), and (3) Fundacion Instituto Leloir-CONICET, Universidad Nacional de San Martin, Laboratorio Lemos SRL, Universidad de Buenos Aires (COVIDAR Argentina Consortium, Buenos Aires, Argentina).
    Consent: All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Antibodies against SARS-CoV2 (2B3E5 from Dr. Thomas Moran and GTX632604 from GeneTex), ACE2 (66699-1-Ig from Proteintech and Rb ab108252 from abcam), VSV-G (A00199 from Genescript), VSV-M (EB0011 from Kerafast), anti-HA (NB600-363 from Novus), and CoX IV (926-42214 from LI-COR) were used.
    SARS-CoV2
    suggested: None
    GTX632604
    suggested: (GeneTex Cat# GTX632604, RRID:AB_2864418)
    ACE2
    suggested: (Abcam Cat# ab108252, RRID:AB_10864415)
    VSV-G
    suggested: None
    anti-HA
    suggested: (Novus Cat# NB600-363, RRID:AB_10001504)
    For secondary staining, membranes were washed and incubated with the appropriate Alexa Fluor 647-conjugated anti-mouse antibody or Alexa Fluor 647-conjugated anti-rabbit antibody.
    anti-mouse
    suggested: None
    anti-rabbit
    suggested: None
    IgG and IgM antibodies were detected with secondary antibodies conjugated to HRP (Millipore AP101P for anti-Human IgG and Invitrogen A18841 for anti-Human IgM).
    IgM
    suggested: (Millipore Cat# AP101P, RRID:AB_92409)
    anti-Human IgG
    suggested: (Thermo Fisher Scientific Cat# A18841, RRID:AB_2535618)
    anti-Human IgM
    suggested: None
    Forty-eight hours post infection, cells were fixed in 10% PFA and stained with mouse anti-SARS-CoV nucleoprotein antibody.
    anti-SARS-CoV nucleoprotein
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    293T and Vero-CCL81 cells were selected with 2 or 10μg/mL of puromycin, respectively.
    293T
    suggested: None
    To generate ACE2 and TMPRSS2 expressing 293T cells, 293T-ACE2 cells were transduced with the VSV-G pseudotyped lentivirus packaging TMPRSS2.
    293T-ACE2
    suggested: RRID:CVCL_YZ65)
    Briefly, ~600 50% tissue culture infectious doses (TCID50) of virus was incubated with a serial dilution of patient sera for 1hr at 37°C prior to infection of Vero-E6 cells.
    Vero-E6
    suggested: None
    For the VNAs performed in our lab (ISMMS-1), a pre-titrated amount of pseudotyped particles (diluted to give approximately 105 RLU) was incubated with a 4-fold serial dilution of patient sera for 30 minutes at room temperature prior to infection of Vero-CCL81 cells seeded the previous day.
    Vero-CCL81
    suggested: None
    Software and Algorithms
    SentencesResources
    VSV-G pseudotyped lentiviruses packaging ACE2 or TMPRSS2 expression constructs were generated by using Bio-T (Bioland; B01-01) to transfect 293T cells with the second-generation lentiviral packaging plasmid (Addgene; 12259), pCAGG-VSV-G, and the desired expression construct (i.e. ACE2 or TMPRSS2).
    Addgene
    suggested: (Addgene, RRID:SCR_002037)
    Background was subtracted from the OD values, samples were determined to be positive if ≥ 3 fold over the negative control and AUC was calculated in PRISM.
    PRISM
    suggested: (PRISM, RRID:SCR_005375)

    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.
    • Thank you for including a protocol registration statement.

    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. SciScore for 10.1101/2020.08.13.20157222: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementSera acquisition All patient sera were acquired after approval by the respective institutional review boards and/or equivalent oversight bodies (Bioethics Committee, Independent Ethics Committee) are indicated: (1) Mount Sinai Hospital Institutional Review Board (New York, USA), (2) Louisiana State University Health Sciences Center – Shreveport (LSUHS, Louisiana, USA), and (3) Fundacion Instituto Leloir-CONICET, Universidad Nacional de San Martin, Laboratorio Lemos SRL, Universidad de Buenos Aires (COVIDAR Argentina Consortium, Buenos Aires, Argentina).Randomizationnot detected.Blindingnot detected.Power Analysisnot detected.Sex as a biological variablenot detected.Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Antibodies against SARS-CoV2 (2B3E5 from Dr. Thomas Moran and GTX632604 from GeneTex), ACE2 (66699-1-Ig from Proteintech and Rb ab108252 from abcam), VSV-G (A00199 from Genescript), VSV-M (EB0011 from Kerafast), anti-HA (NB600-363 from Novus), and CoX IV (926-42214 from LI-COR) were used.
    SARS-CoV2
    suggested: (EnCor Biotechnology Cat# MCA-2G1, RRID:AB_2861173)
    GTX632604
    suggested: None
    ACE2
    suggested: (Abcam Cat# ab108252, RRID:AB_10864415)
    VSV-G
    suggested: None
    anti-HA
    suggested: (Novus Cat# NB600-363, RRID:AB_10001504)
    For secondary staining, membranes were washed and incubated with the appropriate Alexa Fluor 647-conjugated anti-mouse antibody or Alexa Fluor 647-conjugated anti-rabbit antibody.
    anti-mouse
    suggested: None
    anti-rabbit
    suggested: None
    IgG and IgM antibodies were detected with secondary antibodies conjugated to HRP (Millipore AP101P for anti-Human IgG and Invitrogen A18841 for anti-Human IgM).
    IgM
    suggested: (Millipore Cat# AP101P, RRID:AB_92409)
    anti-Human IgG
    suggested: (Thermo Fisher Scientific Cat# A18841, RRID:AB_2535618)
    anti-Human IgM
    suggested: None
    Forty-eight hours post infection, cells were fixed in 10% PFA and stained with mouse anti-SARS-CoV nucleoprotein antibody.
    anti-SARS-CoV nucleoprotein
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    To generate ACE2 and TMPRSS2 expressing 293T cells, 293T-ACE2 cells were transduced with the VSV-G pseudotyped lentivirus packaging TMPRSS2.
    293T-ACE2
    suggested: None
    Briefly, ~600 50% tissue culture infectious doses (TCID50) of virus was incubated with a of patient sera for 1hr at 37ºC prior to infection of Vero-E6 cells.
    Vero-E6
    suggested: None
    Data is presented as mean +/- SEM from two independent experiments done in technical triplicates. *, CoV2pp were used to infect Vero- CCL81 cells in the presence of a 4-fold of patient sera as described in the Methods.
    Vero- CCL81
    suggested: None
    For statistics, ns = not significant, ** is a p-value <0.01, and **** is a p-value <0.0001. ( B) Western blot of ACE2 expression in 293T cell lines.
    293T
    suggested: KCB Cat# KCB 200744YJ, RRID:CVCL_0063)
    Software and Algorithms
    SentencesResources
    VSV-G pseudotyped lentiviruses packaging ACE2 or TMPRSS2 expression constructs were generated by using Bio-T (Bioland; B01-01) to transfect 293T cells with the second-generation lentiviral packaging plasmid (Addgene; 12259), pCAGG-VSV-G, and the desired expression construct (i.e. ACE2 or TMPRSS2).
    Addgene
    suggested: (Addgene, RRID:SCR_002037)
    Background was subtracted from the OD values, samples were determined to be positive if ≥3 fold over the negative control and AUC was calculated in PRISM.
    PRISM
    suggested: (PRISM, RRID:SCR_005375)

    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 Barzooka: We found bar graphs of continuous data. We recommend replacing bar graphs with more informative graphics, as many different datasets can lead to the same bar graph. The actual data may suggest different conclusions from the summary statistics. For more information, please see Weissgerber et al (2015).


    Results from JetFighter: We did not find any issues relating to colormaps.


    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.