Intramuscular SARS-CoV-2 vaccines elicit varying degrees of plasma and salivary antibody responses as compared to natural infection

  1. George Ronald Nahass
  2. Rachel E. Salomon-Shulman
  3. Grace Blacker
  4. Kazim Haider
  5. Rich Brotherton
  6. Kristine Teague
  7. Ying Ying Yiu
  8. Rachel E. Brewer
  9. Sarah Danielle Galloway
  10. Paige Hansen
  11. Gabriel Marquez-Arreguin
  12. Salma Sheikh-Mohamed
  13. Gary Y.C. Chao
  14. Baweleta Isho
  15. Evan Do
  16. Iris Chang
  17. Theo Snow
  18. Alexandra S. Lee
  19. STANFORD COVID-19 BIOBANK
  20. Monali Manohar
  21. Samuel Yang
  22. Andra L. Blomkalns
  23. Angela J Rogers
  24. Allison McGeer
  25. Anne-Claude Gingras
  26. Sharon Straus
  27. Phillip Grant
  28. Kari C. Nadeau
  29. Catherine A. Blish
  30. Jennifer L. Gommerman
  31. Erin C. Sanders
  32. Irving L. Weissman
  33. Michal Caspi Tal

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Abstract

Vaccination induced antibody and T-cell immune responses are important for systemic protection from COVID-19. Because SARS-CoV-2 infects and is transmitted by oral-pharyngeal mucosa, we wished to test mucosal antibodies elicited by natural infection or intramuscular vaccine injection. In a non-randomized observational study, we measured antibodies against the SARS-CoV-2 RBD in plasma and saliva from convalescent or vaccinated individuals and tested their neutralizing potential using a replication competent rVSV-eGFP-SARS-CoV-2. We found IgG and IgA anti-RBD antibodies as well as neutralizing activity in convalescent plasma and saliva. Two doses of mRNA vaccination (BNT162b2 or mRNA-1273) induced high levels of IgG anti-RBD in saliva, a subset of whom also had IgA, and significant neutralizing activity. We detected anti-RBD IgG and IgA with significant neutralizing potential in the plasma of single dose Ad26.COV2.S vaccinated individuals, and we detected slight amounts of anti-RBD antibodies in matched saliva. The role of salivary antibodies in protection against SARS-CoV-2 infection is unknown and merits further investigation. This study was not designed to, nor did it study the full kinetics of the antibody response or protection from infection, nor did it address variants of SARS-CoV-2.

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  1. ScreenIT

    SciScore for 10.1101/2021.08.22.21262168: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: The University of Toronto Research Ethics Board (REB) provided approval for Stanford to conduct antibody analysis of saliva samples to SARS-CoV-2 antigens for samples collected under study number 23901.
    Sex as a biological variableAll participants in this study were between the ages of 18-85, reported their biological sex assigned at birth as either male or female, were not pregnant at the time of sample collection, and self-attested to being healthy at the time of sample collection.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    ETHICS STATEMENT: The Stanford University, School of Medicine Institutional Review Board (IRB) granted approval for recruiting SARS-CoV-2 vaccine trial participants and EUA vaccine recipients to this study for saliva and blood collection and for studying the antibody response to SARS-CoV-2 antigens in those samples (study number 57277 and 55689).
    SARS-CoV-2
    suggested: None
    Gating scheme is shown in supplemental figures 4 and 5 comparing percentage antibody bound to RBD beads and known concentrations of anti-RBD IgG quantified.
    anti-RBD IgG
    suggested: None
    Each sample plate included a dilution of anti-RBD antibody (Invitrogen, Cat. No. 703958) of 10 μg/mL, 5 μg/mL, 1 μg/mL, 0.5 μg/mL, 0.1 μg/mL, and 0.05 μg/mL.
    anti-RBD
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    CELLS: Human Embryonic Kidney (HEK) 293 cells were engineered to encode human angiotensin converting enzyme 2 (hACE2 in the pDEST-mCherry vector) (courtesy of Dr. Siyuan Ding, WUSTL) as previously described (59).
    HEK
    suggested: None
    293
    suggested: NCI-DTP Cat# NCI-293TT, RRID:CVCL_1D85)
    Cells were grown in 5% carbon dioxide (CO2) at 37 °C and passaged every 3 days using Versene solution (Gibco, Cat. No. 15040066). ASSAY: HEK293-hACE2-mCherry cells were seeded at a density of 25,000 cells per well in a 96-well, flat-bottom tissue culture coated plate.
    HEK293-hACE2-mCherry
    suggested: None
    Recombinant DNA
    SentencesResources
    CELLS: Human Embryonic Kidney (HEK) 293 cells were engineered to encode human angiotensin converting enzyme 2 (hACE2 in the pDEST-mCherry vector) (courtesy of Dr. Siyuan Ding, WUSTL) as previously described (59).
    pDEST-mCherry
    suggested: None

    Results from OddPub: Thank you for sharing your code and data.

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Limitations: Researchers are still learning about the biology around these different vaccine formulations, which may elicit distinct types of antibody responses and specifically salivary antibodies. Furthermore, researchers are still learning about the immune components in saliva. For example, the method of assay may require special handling steps such as the pre-adsorption step with materials not containing the RBD or spike protein targets to reveal specific antibodies to the viral targets, as shown by the Gommerman lab ELISA assay(33, 44) and others (45). One limitation of our observational study is that the extent that salivary antibodies contribute to vaccine efficacy remains unknown, and further research should consider how salivary antibodies may explain some differences in observed vaccine efficacy. Antibodies are only one facet of a complex immune response, and therefore an important limitation of our study is that we did not investigate T-cell responses, which are seen to provide immune protection following vaccination even in the absence of protective antibodies. We were surprised to find such high levels of IgG isotype antibodies in the saliva of mRNA vaccinated individuals. In our limited testing, we found salivary IgA anti-RBD in response to natural infection, but not in all mRNA vaccinated individuals. Humans practice oral hygiene and perturbations to the mucosa that experimental animals do not. The elements of oral hygiene can lead to injury where individuals w...

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04373148RecruitingUnderstanding Immunity to SARS-CoV-2, the Coronavirus Causin…
    NCT04505722Active, not recruitingA Study of Ad26.COV2.S for the Prevention of SARS-CoV-2-Medi…

    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.

    About SciScore

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  2. Version published to 10.1101/2021.08.22.21262168v1 on medRxiv