EMoMiS: A Pipeline for Epitope-based Molecular Mimicry Search in Protein Structures with Applications to SARS-CoV-2

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Abstract

Motivation

Epitope-based molecular mimicry occurs when an antibody cross-reacts with two different antigens due to structural and chemical similarities. Molecular mimicry between proteins from two viruses can lead to beneficial cross-protection when the antibodies produced by exposure to one also react with the other. On the other hand, mimicry between a protein from a pathogen and a human protein can lead to auto-immune disorders if the antibodies resulting from exposure to the virus end up interacting with host proteins. While cross-protection can suggest the possible reuse of vaccines developed for other pathogens, cross-reaction with host proteins may explain side effects. There are no computational tools available to date for a large-scale search of antibody cross-reactivity.

Results

We present a comprehensive Epitope-based Molecular Mimicry Search ( EMoMiS ) pipeline for computational molecular mimicry searches. EMoMiS , when applied to the SARS-CoV-2 Spike protein, identified eight examples of molecular mimicry with viral and human proteins. These findings provide possible explanations for (a) differential severity of COVID-19 caused by cross-protection due to prior vaccinations and/or exposure to other viruses, and (b) commonly seen COVID-19 side effects such as thrombocytopenia and thrombophilia. Our findings are supported by previously reported research but need validation with laboratory experiments. The developed pipeline is generic and can be applied to find mimicry for novel pathogens. It has applications in improving vaccine design.

Availability

The developed Epitope-based Molecular Mimicry Search Pipeline ( EMoMiS ) is available from https://biorg.cs.fiu.edu/emomis/ .

Contact

giri@cs.fiu.edu

Article activity feed

  1. SciScore for 10.1101/2022.02.05.479274: (What is this?)

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

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    Antibodies
    SentencesResources
    The Molecular Surface Interaction Fingerprint Search (MaSIF-Search) that uses a geometric deep learning approach was used to evaluate antibody-antigen binding, (Gainza et al., 2020).
    antibody-antigen binding,
    suggested: None
    In Step D of the EMoMiS pipeline, we evaluate the structurally similar motifs for the binding strength of the antibody-antigen pair.
    antibody-antigen pair.
    suggested: None
    Software and Algorithms
    SentencesResources
    The EMoMiS pipeline uses the three-dimensional structures, SDB as well as sequence information, QDB of antibody-antigen complexes from the structural antibody database SAbDab (Dunbar et al., 2014).
    EMoMiS
    suggested: None
    In Step D, we evaluate the potential cross-reactivity using a pre-trained deep learning model (Gainza et al., 2020), which estimates the binding strength between the antibody SDB-Ab, complexed with the database antigen SDB and the target antigen Starget-Ag.. 2.1. Sequence Similarity Search: The sequence similarity search between the target protein sequence, Qtarget, and the antigen sequences from the data set, QDB, was performed using Protein-Protein BLAST 2.12.0+ (Altschul, 1997).
    Protein-Protein
    suggested: (Protein-protein interfaces, RRID:SCR_007879)
    BLAST
    suggested: (BLASTX, RRID:SCR_001653)
    FASTA sequences were downloaded using BioPython utilities (Cock et al., 2009).
    BioPython
    suggested: (Biopython, RRID:SCR_007173)
    For 3000 random antigens from the SAbDab database, we isolated possible epitopes of lengths ranging from 3 to 32 AA, such that the center of each motif was in contact with its native antibody.
    SAbDab
    suggested: None
    To ensure reproducibility, the running environment was containerized with Singularity version 3.8.5 (Kurtzer et al., 2017).
    Singularity
    suggested: (Singularity Hub, RRID:SCR_016248)

    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: We detected the following sentences addressing limitations in the study:
    Another limitation of the deep learning model is the absence of glycans in the set of features. The glycosylation events may significantly affect the antibody neutralizing properties and thus, the model sensitivity (Miranda et al., 2007). Those limiting factors may consolidate the false-negative predictions. For example, the score for the antibody from the Ab-Spike OC43 complex (PDB ID 7M51) to bind SARS-CoV-2 Spike protein (PDB ID 7M53) was very low (DL score = 3.066, p-value = 0.306, see Supplemental Table S3). Yet, the cross-reaction between antibody B6 (PDB IDs 7M51 and 7M53) with coronavirus OC43 and SARS-CoV-2 Spike proteins was experimentally verified (Sauer et al., 2021). On the other hand, another Spike configuration (PDB ID 7RNJ) was found to cross-react with coronavirus OC43 (Table 1, H), which highlights the advantage of using multiple target structures. While the lack of a molecular structure for the target protein may be seen as a limitation for the EMoMiS pipeline, protein structures can be quickly and accurately predicted with the recent advances in the deep learning field (Jumper et al., 2021). 4.2. Antiviral Antibody Cross-reaction: The EMoMiS pipeline identified four sites in the SARS-CoV-2 Spike protein that may mimic epitopes from other viruses. Antibody cross-reaction with viral mimic epitopes may provide cross-protection to the host. On the other hand, antibodies elicited by mimicry may cross-react with the vital antigen with lower affinity. As a result...

    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.

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


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