Spike-Dependent Opsonization Indicates Both Dose-Dependent Inhibition of Phagocytosis and That Non-Neutralizing Antibodies Can Confer Protection to SARS-CoV-2

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Abstract

Spike-specific antibodies are central to effective COVID19 immunity. Research efforts have focused on antibodies that neutralize the ACE2-Spike interaction but not on non-neutralizing antibodies. Antibody-dependent phagocytosis is an immune mechanism enhanced by opsonization, where typically, more bound antibodies trigger a stronger phagocyte response. Here, we show that Spike-specific antibodies, dependent on concentration, can either enhance or reduce Spike-bead phagocytosis by monocytes independently of the antibody neutralization potential. Surprisingly, we find that both convalescent patient plasma and patient-derived monoclonal antibodies lead to maximum opsonization already at low levels of bound antibodies and is reduced as antibody binding to Spike protein increases. Moreover, we show that this Spike-dependent modulation of opsonization correlate with the outcome in an experimental SARS-CoV-2 infection model. These results suggest that the levels of anti-Spike antibodies could influence monocyte-mediated immune functions and propose that non-neutralizing antibodies could confer protection to SARS-CoV-2 infection by mediating phagocytosis.

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  1. SciScore for 10.1101/2021.10.14.464464: (What is this?)

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

    Table 1: Rigor

    EthicsConsent: All participants gave written informed consent to participate in the study which was approved by the Swedish ethical review authority (2020/01747).
    IRB: All the animal experiments were performed under the approval of the regional animal experimental ethics committee in Stockholm (16765-2020).
    Sex as a biological variableAnimal experiments: Forty-two nine-week old female K18 hACE2 (B6.Cg-Tg(K18-ACE2)2Prlmn/J) mice were inoculated intranasally with 105 PFU of SARS-CoV-2 (Wuhan strain, isolate SARS-CoV-2/01/human/2020/SWE, sourced from the Swedish Health Authorities).
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The cells were then washed with PBS, blocked in 2% BSA and stained with antibodies against CD19-PE (BD-555413), CD3-BV510 (BD-564713), IgG-BV421 (BD-562581) and a live/Dead Sytox stain.
    CD19-PE
    suggested: None
    CD3-BV510
    suggested: None
    BD-564713) , IgG-BV421
    suggested: None
    BD-562581
    suggested: None
    After 1 hour incubation at room temperature the wells were washed and bound scFv was detected by incubation for 40 minutes at room temperature with peroxidase labelled monoclonal anti-FLAG® M2 antibody (Sigma Aldrich (30 µl diluted 1/4000 in assay buffer) and development using 1-Step™ Ultra TMB-ELISA Substrate Solution (Thermo Fisher Scientific)
    anti-FLAG®
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    HEK293 cells constitutively expressing the ACE2 receptor were acquired from BEI resources (NR-52511).
    HEK293
    suggested: None
    THP-1 cells were washed twice with PBS and reconstituted in Sodium medium.
    THP-1
    suggested: CLS Cat# 300356/p804_THP-1, RRID:CVCL_0006)
    Pseudotyped lentiviruses displaying the SARS-CoV-2 pandemic founder variant (Wu-Hu-1) packaging a firefly luciferase reporter gene were generated by the co-transfection of HEK293T cells using Lipofectamine 3000 (Invitrogen) per the manufacturer’s protocols.
    HEK293T
    suggested: None
    For these experiments, the HEK293T-hACE2 cell culture was supplemented with penicillin/streptomycin antibiotics to avoid contamination.
    HEK293T-hACE2
    suggested: RRID:CVCL_A7UK)
    Bead-based neutralization assay: HEK293T-ACE2 cells were seeded at density of 35,000 cells per well in a Poly-D-Lysine coated flat bottom 96 well plate.
    HEK293T-ACE2
    suggested: None
    Experimental Models: Organisms/Strains
    SentencesResources
    Animal experiments: Forty-two nine-week old female K18 hACE2 (B6.Cg-Tg(K18-ACE2)2Prlmn/J) mice were inoculated intranasally with 105 PFU of SARS-CoV-2 (Wuhan strain, isolate SARS-CoV-2/01/human/2020/SWE, sourced from the Swedish Health Authorities).
    B6.Cg-Tg(K18-ACE2)2Prlmn/J
    suggested: RRID:IMSR_JAX:034860)
    Software and Algorithms
    SentencesResources
    Once received, we collated the V(D)J regions from our antibodies of interest using the V-Loupe software (10X Genomics software platform).
    Genomics
    suggested: (UTHSCSA Genomics Core, RRID:SCR_012239)
    Multiple sequence alignment using the ClustalW algorithm was performed on the light chain sequences and the heavy chain sequences.
    ClustalW
    suggested: (ClustalW, RRID:SCR_017277)
    Apparent reaction rate kinetics was determined using a Langmuir 1:1 model using the Sierra Analyser software version 3.4.3 (Bruker).
    Sierra Analyser
    suggested: (OMICtools, RRID:SCR_002250)

    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: Please consider improving the rainbow (“jet”) colormap(s) used on page 4. At least one figure is not accessible to readers with colorblindness and/or is not true to the data, i.e. not perceptually uniform.


    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.

    Results from scite Reference Check: We found no unreliable references.


    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.