Subacute SARS-CoV-2 replication can be controlled in the absence of CD8+ T cells in cynomolgus macaques

  1. Takushi Nomura
  2. Hiroyuki Yamamoto
  3. Masako Nishizawa
  4. Trang Thi Thu Hau
  5. Shigeyoshi Harada
  6. Hiroshi Ishii
  7. Sayuri Seki
  8. Midori Nakamura-Hoshi
  9. Midori Okazaki
  10. Sachie Daigen
  11. Ai Kawana-Tachikawa
  12. Noriyo Nagata
  13. Naoko Iwata-Yoshikawa
  14. Nozomi Shiwa
  15. Shun Iida
  16. Harutaka Katano
  17. Tadaki Suzuki
  18. Eun-Sil Park
  19. Ken Maeda
  20. Yuriko Suzaki
  21. Yasushi Ami
  22. Tetsuro Matano

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Abstract

SARS-CoV-2 infection presents clinical manifestations ranging from asymptomatic to fatal respiratory failure. Despite the induction of functional SARS-CoV-2-specific CD8 + T-cell responses in convalescent individuals, the role of virus-specific CD8 + T-cell responses in the control of SARS-CoV-2 replication remains unknown. In the present study, we show that subacute SARS-CoV-2 replication can be controlled in the absence of CD8 + T cells in cynomolgus macaques. Eight macaques were intranasally inoculated with 10 5 or 10 6 TCID 50 of SARS-CoV-2, and three of the eight macaques were treated with a monoclonal anti-CD8 antibody on days 5 and 7 post-infection. In these three macaques, CD8 + T cells were undetectable on day 7 and thereafter, while virus-specific CD8 + T-cell responses were induced in the remaining five untreated animals. Viral RNA was detected in nasopharyngeal swabs for 10–17 days post-infection in all macaques, and the kinetics of viral RNA levels in pharyngeal swabs and plasma neutralizing antibody titers were comparable between the anti-CD8 antibody treated and untreated animals. SARS-CoV-2 RNA was detected in the pharyngeal mucosa and/or retropharyngeal lymph node obtained at necropsy on day 21 in two of the untreated group but undetectable in all macaques treated with anti-CD8 antibody. CD8 + T-cell responses may contribute to viral control in SARS-CoV-2 infection, but our results indicate possible containment of subacute viral replication in the absence of CD8 + T cells, implying that CD8 + T-cell dysfunction may not solely lead to viral control failure.

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  1. Version published to 10.1371/journal.ppat.1009668
  2. ScreenIT

    SciScore for 10.1101/2021.05.26.445769: (What is this?)

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

    Table 1: Rigor

    EthicsIACUC: (NIID) after approval by the Committee on the Ethics of Animal Experiments in NIID (permission number: 520001) under the guidelines for animal experiments in accordance with the Guidelines for Proper Conduct of Animal Experiments established by the Science Council of Japan (http://www.scj.go.jp/ja/info/kohyo/pdf/kohyo-20-k16-2e.pdf).
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Cell Line Authenticationnot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Virus inoculation, blood collection, nasopharyngeal and throat swab collection, and anti-CD8 antibody treatment were performed under ketamine anesthesia.
    anti-CD8
    suggested: None
    Three (Group D) of the nine macaques were intravenously administrated with 5 mg/kg body weight of anti-CD8α antibody clone MT807 (NIH Nonhuman Primate Reagent Resource) on days 5 and 7 post-infection.
    anti-CD8α
    suggested: None
    anti-CD8 PerCP (SK1; BD), and anti-CD20 PE (2H7; BD) antibodies.
    anti-CD20 PE
    suggested: None
    Alternatively, whole blood samples from anti-CD8 antibody-treated animals were stained with anti-CD3 APC-Cy7, anti-CD4 PerCP (L200; BD)
    anti-CD3
    suggested: None
    anti-CD4
    suggested: None
    Experimental Models: Cell Lines
    SentencesResources
    Virus recovery from swabs: Vero E6/TMPRSS2 cells in 96-well plates were added with 10-fold serially diluted swab solutions and cultured for 4 days without medium change.
    Vero E6/TMPRSS2
    suggested: None
    After incubation for 45 min at room temperature, 20 μl of the mixture was added to each of four wells (1 x 104 Vero cells/well) in a 96-well plate.
    Vero
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistical analysis: Statistical analyses were performed using Prism software (GraphPad Software, Inc.) with significance set at p values of < 0.05.
    Prism
    suggested: (PRISM, RRID:SCR_005375)
    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.
    • No funding statement was detected.
    • 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.

  3. Version published to 10.1101/2021.05.26.445769v1 on bioRxiv