Elevated Humoral Immune Response to SARS-CoV-2 at High Altitudes Revealed by an Anti-RBD “In-House” ELISA

  1. Rodrigo Hernán Tomas-Grau
  2. Diego Ploper
  3. César Luis Ávila
  4. Esteban Vera Pingitore
  5. Carolina Maldonado Galdeano
  6. Silvina Chaves
  7. Sergio Benjamín Socias
  8. Agustín Stagnetto
  9. Silvia Adriana Navarro
  10. Rossana Elena Chahla
  11. Mónica Aguilar López
  12. Conrado Juan Llapur
  13. Patricia Aznar
  14. María Elena Alcorta
  15. Dardo Costas
  16. Isolina Flores
  17. Dar Heinze
  18. Gabriela Apfelbaum
  19. Raul Mostoslavsky
  20. Gustavo Mostoslavsky
  21. Silvia Inés Cazorla
  22. Gabriela del Valle Perdigón
  23. Rosana Chehín

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Abstract

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused a global pandemic with dramatic health and socioeconomic consequences. The Coronavirus Disease 2019 (COVID-19) challenges health systems to quickly respond by developing new diagnostic strategies that contribute to identify infected individuals, monitor infections, perform contact-tracing, and limit the spread of the virus. In this brief report, we developed a highly sensitive, specific, and precise “ In-House ” ELISA to correctly discriminate previously SARS-CoV-2-infected and non-infected individuals and study population seroprevalence. Among 758 individuals evaluated for anti-SARS-CoV-2 serology in the province of Tucumán, Argentina, we found a weak correlation between antibodies elicited against the RBD, the receptor-binding domain of the Spike protein, and the nucleocapsid (N) antigens of this virus. Additionally, we detected mild levels of anti-RBD IgG antibodies in 33.6% of individuals diagnosed with COVID-19, while only 19% showed sufficient antibody titers to be considered as plasma donors. No differences in IgG anti-RBD titers were found between women and men, neither in between different age groups ranging from 18 to 60. Surprisingly, individuals from a high altitude village displayed elevated and longer lasting anti-RBD titers compared to those from a lower altitude city. To our knowledge, this is the first report correlating altitude with increased humoral immune response against SARS-CoV-2 infection.

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  1. Version published to 10.3389/fmed.2021.720988
  2. ScreenIT

    SciScore for 10.1101/2021.03.10.21252711: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: The procedures were approved by the Bioethics Committee of the SIPROSA N° 29/2020.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    ELISA anti-RBD antibody binding assay: An indirect ELISA test for the determination of IgG anti–RBD antibody was design.
    anti-RBD
    suggested: None
    anti–RBD
    suggested: None
    Peroxidase-conjugated immunoglobulins to human IgG (whole molecule) -Peroxidase (Sigma A8667) diluted 1/35,000 were used as a secondary antibody.
    human IgG ( whole molecule ) -Peroxidase
    suggested: None
    human IgG ( whole molecule )
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    HEK293 were grown in high glucose medium supplemented with 10% fetal bovine serum and antibiotic/antimycotic and PEI 87 kDa was used as the transfection reagent.
    HEK293
    suggested: None
    Software and Algorithms
    SentencesResources
    RBD-IgG titers, and correlation and differences between medias studies were carried out with the Prisma 8.0 Software (GraphPad, San Diego, CA).
    GraphPad
    suggested: (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.

    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.

  3. Version published to 10.1101/2021.03.10.21252711v1 on medRxiv