Rapid selection of a human monoclonal antibody that potently neutralizes SARS-CoV-2 in two animal models
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Abstract
Effective therapies are urgently needed for the SARS-CoV-2/COVID19 pandemic. We identified panels of fully human monoclonal antibodies (mAbs) from eight large phage-displayed Fab, scFv and VH libraries by panning against the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) glycoprotein. One high affinity mAb, IgG1 ab1, specifically neutralized replication competent SARS-CoV-2 with exceptional potency as measured by two different assays. There was no enhancement of pseudovirus infection in cells expressing Fcγ receptors at any concentration. It competed with human angiotensin-converting enzyme 2 (hACE2) for binding to RBD suggesting a competitive mechanism of virus neutralization. IgG1 ab1 potently neutralized mouse ACE2 adapted SARS-CoV-2 in wild type BALB/c mice and native virus in hACE2 expressing transgenic mice. The ab1 sequence has relatively low number of somatic mutations indicating that ab1-like antibodies could be quickly elicited during natural SARS-CoV-2 infection or by RBD-based vaccines. IgG1 ab1 does not have developability liabilities, and thus has potential for therapy and prophylaxis of SARS-CoV-2 infections. The rapid identification (within 6 days) of potent mAbs shows the value of large antibody libraries for response to public health threats from emerging microbes.
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SciScore for 10.1101/2020.05.13.093088: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IACUC: The study was carried out in accordance with the recommendations for care and use of animals by the Office of Laboratory Animal Welfare (OLAW), National Institutes of Health and the Institutional Animal Care and Use Committee (IACUC) of University of North Carolina (UNC permit no. A-3410-01). Randomization The Fab and scFv libraries were constructed by randomly pairing antibody VH and VL gene, and the VH libraries -by grafting CDRs into stable VH scaffolds. Blinding not detected. Power Analysis not detected. Sex as a biological variable Groups of 5 each of 10 to 12-month old female BALB/c mice (Envigo, #047) were treated prophylactically (12 hours before … SciScore for 10.1101/2020.05.13.093088: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IACUC: The study was carried out in accordance with the recommendations for care and use of animals by the Office of Laboratory Animal Welfare (OLAW), National Institutes of Health and the Institutional Animal Care and Use Committee (IACUC) of University of North Carolina (UNC permit no. A-3410-01). Randomization The Fab and scFv libraries were constructed by randomly pairing antibody VH and VL gene, and the VH libraries -by grafting CDRs into stable VH scaffolds. Blinding not detected. Power Analysis not detected. Sex as a biological variable Groups of 5 each of 10 to 12-month old female BALB/c mice (Envigo, #047) were treated prophylactically (12 hours before infection) intraperitoneally with 900 μg, 200 μg, or 50 μg of IgG1 ab1, respectively. Cell Line Authentication not detected. Table 2: Resources
Antibodies Sentences Resources Generation, Expression and Characterization of SARS-CoV-2 RBD-Fc, S1-Fc, ACE2-Fc and CR3022 Fab: The SARS-CoV-2 surface glycoprotein and the anti-SARS-CoV antibody IgG1 CR3022 (31) and IgG1 S230 genes were synthesized by IDT (Coralville, Iowa). S1-Fcsuggested: NoneACE2-Fcsuggested: NoneSARS-CoV-2 surface glycoproteinsuggested: Noneanti-SARS-CoVsuggested: NoneIgG1suggested: NoneMERS-CoV-specific IgG1 m336 antibody was expressed in human mammalian cell as described previously (5). MERS-CoV-specific IgG1suggested: NoneAfter washing, bound IgG1 CR3022 was detected by HRP-conjugated anti human Fc antibody. anti human Fc antibody.suggested: NoneThen cells were resuspended to 100 μl PBSA buffer followed by addition of 1 μl PE conjugated anti-human Fc antibody (Sigma-Aldrich) and incubate at 4 °C for 30 min. anti-human Fcsuggested: NoneFcγRs expression level was FACS tested by using FITC conjugated anti-FcγR antibody (Invitrogen). anti-FcγRsuggested: NoneExperimental Models: Cell Lines Sentences Resources Briefly, HIV-1 backbone based pseudovirus was packaged in 293T cells by co-transfecting with plasmid encoding SARS-CoV-2 S protein and plasmid encoding luciferase expressing HIV-1 genome (pNL4-3.luc.RE) using polyethylenimine (PEI). 293Tsuggested: NoneAdditionally, Vero E6 cells treated with the MERS-CoV RBD-specific neutralizing m336 mAb (5) were included as additional controls. Vero E6suggested: NoneThe entire library of plasmids is arrayed in duplicate in a matrix format and transfected into HEK-293T cells, followed by incubation for 36 h to allow protein expression. HEK-293Tsuggested: NoneExperimental Models: Organisms/Strains Sentences Resources Groups of 5 each of 10 to 12-month old female BALB/c mice (Envigo, #047) were treated prophylactically (12 hours before infection) intraperitoneally with 900 μg, 200 μg, or 50 μg of IgG1 ab1, respectively. BALB/csuggested: NoneEthics statement: Human ACE2 transgenic C3B6 mice (6–9 weeks old) and BALB/c mice (10-12 weeks old) were used for all experiments. C3B6suggested: NoneSoftware and Algorithms Sentences Resources The concentrations at which IgG1 ab1 or hACE2-Fc achieved 50% PE-A+ cells (EC50) was obtained by fitting using the equation of “[agonist] vs. response -- variable slope (four parameter)” in the Graphpad Prism 7 (San Diego, CA). Graphpadsuggested: (GraphPad, RRID:SCR_000306)Statistical analyses: The statistical significance of difference between IgG1 treated and control mice lung virus titers was analyzed by the one-tailed Mann Whitney U test calculated using GraphPad Prism 7.0. GraphPad Prismsuggested: (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: 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.
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