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Helminth induced monocytosis conveys protection from respiratory syncytial virus infection in mice.
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  • Matthew Burgess O,
  • Piotr Janas,
  • Karla Berry,
  • Hannah Mayr,
  • Matthias Mack,
  • Stephen Jenkins J,
  • Calum Bain C,
  • Henry J. McSorley,
  • Jürgen Schwarze
Matthew Burgess O
The University of Edinburgh Centre for Inflammation Research
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Piotr Janas
The University of Edinburgh Centre for Inflammation Research
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Karla Berry
The University of Edinburgh Centre for Inflammation Research
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Hannah Mayr
Medizinische Universitat Wien
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Matthias Mack
Universitat Regensburg
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Stephen Jenkins J
The University of Edinburgh Centre for Inflammation Research
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Calum Bain C
The University of Edinburgh Centre for Inflammation Research
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Henry J. McSorley
University of Dundee Division of Cell Signalling and Immunology
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Jürgen Schwarze
The University of Edinburgh Centre for Inflammation Research

Corresponding Author:[email protected]

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Abstract

Background Respiratory syncytial virus (RSV) infection in infants is a major cause of viral bronchiolitis and hospitalisation. We have previously shown in a murine model that ongoing infection with the gut helminth Heligmosomoides polygyrus ( H. polygyrus) protects against RSV infection through type I interferon (IFN-I) dependent reduction of viral load. Yet, the cellular basis for this protection has remained elusive. Given that recruitment of mononuclear phagocytes to the lung is critical for early RSV infection control, we assessed their role in this coinfection model. Methods Mice were infected by oral gavage with H. polygyrus. Myeloid immune cell populations were assessed by flow cytometry in lung, blood and bone marrow throughout infection and after secondary infection with RSV. Monocyte numbers were depleted by anti-CCR2 antibody or increased by intravenous transfer of enriched monocytes. Results H. polygyrus infection induces bone marrow monopoiesis, increasing circulatory monocytes and lung mononuclear phagocytes in a IFN-I signalling dependent manner. This expansion causes enhanced lung mononuclear phagocyte counts early in RSV infection that may contribute to the reduction of RSV load. Depletion or supplementation of circulatory monocytes prior to RSV infection confirms that these are both necessary and sufficient for helminth induced antiviral protection. Conclusions H. polygyrus infection induces systemic monocytosis contributing to elevated mononuclear phagocyte numbers in the lung. These cells are central to an anti-viral effect that reduces the peak viral load in RSV infection. Treatments to promote or modulate these cells may provide novel paths to control RSV infection in high risk individuals.
11 May 2023Submitted to Allergy
11 May 2023Submission Checks Completed
11 May 2023Assigned to Editor
11 May 2023Review(s) Completed, Editorial Evaluation Pending
16 May 2023Reviewer(s) Assigned
16 Jun 2023Editorial Decision: Revise Minor
15 Apr 20241st Revision Received
18 Apr 2024Review(s) Completed, Editorial Evaluation Pending
08 May 2024Editorial Decision: Accept