A cocktail containing two synergetic antibodies broadly neutralizes SARS-CoV-2 and its variants including Omicron BA.1 and BA.2
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Abstract
Neutralizing antibodies (NAbs) can prevent and treat infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, continuously emerging variants, such as Omicron, have significantly reduced the potency of most known NAbs. The selection of NAbs with broad neutralizing activities and the identification of conserved critical epitopes are still urgently needed. Here, we identified an extremely potent antibody (55A8) by single B-cell sorting from convalescent SARS-CoV-2-infected patients that recognized the receptor-binding domain (RBD) in the SARS-CoV-2 spike (S) protein. 55A8 could bind to wild-type SARS-CoV-2, Omicron BA.1 and Omicron BA.2 simultaneously with 58G6, a NAb previously identified by our group. Importantly, an antibody cocktail containing 55A8 and 58G6 (2-cocktail) showed synergetic neutralizing activity with a half-maximal inhibitory concentration (IC 50 ) in the picomolar range in vitro and prophylactic efficacy in hamsters challenged with Omicron (BA.1) through intranasal delivery at an extraordinarily low dosage (25 μg of each antibody daily) at 3 days post-infection. Structural analysis by cryo-electron microscopy (cryo-EM) revealed that 55A8 is a Class III NAb that recognizes a highly conserved epitope. It could block angiotensin-converting enzyme 2 (ACE2) binding to the RBD in the S protein trimer via steric hindrance. The epitopes in the RBD recognized by 55A8 and 58G6 were found to be different and complementary, which could explain the synergetic mechanism of these two NAbs. Our findings not only provide a potential antibody cocktail for clinical use against infection with current SARS-CoV-2 strains and future variants but also identify critical epitope information for the development of better antiviral agents.
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SciScore for 10.1101/2022.04.26.489529: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IACUC: Ethics statements: All procedures associated with the animal study were reviewed and approved by the Institutional Animal Care and Use Committee of the Institute of Wuhan Institute of Virology, Chinese Academy of Sciences, and were performed in an ABSL-3 facility (ethical approval number: WIVA45202104). Sex as a biological variable Animals: Female Syrian hamsters (five to six weeks of age) were purchased from Wuhan Institute of Biological Products Co., Ltd. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Antibodies Sentences Resources ALP-conjugated anti-human IgG antibody (ThermoFisher, A18808, 1:2000) was … SciScore for 10.1101/2022.04.26.489529: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IACUC: Ethics statements: All procedures associated with the animal study were reviewed and approved by the Institutional Animal Care and Use Committee of the Institute of Wuhan Institute of Virology, Chinese Academy of Sciences, and were performed in an ABSL-3 facility (ethical approval number: WIVA45202104). Sex as a biological variable Animals: Female Syrian hamsters (five to six weeks of age) were purchased from Wuhan Institute of Biological Products Co., Ltd. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Antibodies Sentences Resources ALP-conjugated anti-human IgG antibody (ThermoFisher, A18808, 1:2000) was used as the detection antibody at 37°C for 30 min . anti-human IgGsuggested: (Thermo Fisher Scientific Cat# A18808, RRID:AB_2535585)A18808suggested: (ABclonal Cat# A18808, RRID:AB_2862443)The first antibody was allowed to associate for 600 s at 20 μg/mL, and the second protein (ACE2 (50 μg/mL) or a mixture of equal amounts of antibodies and ACE2) was allowed to associate for 300 s. ACE2suggested: NoneAnimal protection experiments: To assess whether the 58G6 and 55A8 antibody cocktail induced synergistic effector function responses in vivo, hamsters were infected with 104 PFU of Omicron and treated with 58G6 (1500 μg), 55A8 (500 μg), or the 58G6 and 55A8 mixture (1000 μg of 58G6 and 300 μg of 55A8) at 1 h pre-infection and 24 and 48 h post-infection. 55A8suggested: NoneExperimental Models: Cell Lines Sentences Resources Viral stocks were prepared by propagation in Vero E6 cells (catalog no. ATCC® CRL-1586™) in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin and streptomycin (P/S). Vero E6suggested: NoneAfter 24 h, the luciferase activities of infected 293T/ACE2 cells were detected with the Bright-Luciferase Reporter Assay System (Beyotime, RG055M). 293T/ACE2suggested: RRID:CVCL_YZ65)Software and Algorithms Sentences Resources PRNT50 values were calculated in GraphPad Prism 9. GraphPad Prismsuggested: (GraphPad Prism, RRID:SCR_002798)Cryo-EM data processing: All dose-fractioned images were motion-corrected and dose-weighted with MotionCorr2 software45, and their contrast transfer functions (CTFs) were estimated by cryoSPARC patch CTF estimation46. MotionCorr2suggested: NonecryoSPARCsuggested: (cryoSPARC, RRID:SCR_016501)The 55A8 Fab model was first predicted using Phyre248 and then manually built in Coot 0.949 with the guidance of the cryo-EM electron density maps, and overall real-space refinements were performed using Phenix 1.1950. Phenixsuggested: (Phenix, RRID:SCR_014224)The 58G6 Fab model15 was manually built in Coot 0.9 with the guidance of the cryo-EM electron density maps, and overall real-space refinements were performed using Phenix 1.19. Cootsuggested: (Coot, RRID:SCR_014222)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.
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Results from scite Reference Check: We found no unreliable references.
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