IL-22-binding protein exacerbates influenza, bacterial super-infection

Mucosal Immunol. 2019 Sep;12(5):1231-1243. doi: 10.1038/s41385-019-0188-7. Epub 2019 Jul 11.

Abstract

Secondary bacterial pneumonia is a significant complication of severe influenza infection and Staphylococcus aureus and Streptococcus pneumoniae are the primary pathogens of interest. IL-22 promotes S. aureus and S. pneumoniae host defense in the lung through epithelial integrity and induction of antimicrobial peptides and is inhibited by the soluble decoy receptor IL-22-binding protein (IL-22BP). Little is known about the effect of the IL-22/IL-22BP regulatory pathway on lung infection, and it has not been studied in the setting of super-infection. We exposed wild-type and IL-22BP-/- mice to influenza A/PR/8/34 for 6 days prior to infection with S. aureus (USA300) S. pneumoniae. Super-infected IL-22BP-/- mice had decreased bacterial burden and improved survival compared to controls. IL-22BP-/- mice exhibited decreased inflammation, increased lipocalin 2 expression, and deletion of IL-22BP was associated with preserved epithelial barrier function with evidence of improved tight junction stability. Human bronchial epithelial cells treated with IL-22Fc showed evidence of improved tight junctions compared to untreated cells. This study revealed that IL-22BP-/- mice are protected during influenza, bacterial super-infection, suggesting that IL-22BP has a pro-inflammatory role and impairs epithelial barrier function likely through interaction with IL-22.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Bacterial Infections / genetics
  • Bacterial Infections / metabolism*
  • Bacterial Infections / microbiology*
  • Bacterial Infections / pathology
  • Bacterial Load
  • Blood-Air Barrier / metabolism
  • Blood-Air Barrier / pathology
  • Blood-Air Barrier / virology
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Disease Models, Animal
  • Gene Expression
  • Interleukin-22
  • Interleukins / genetics
  • Interleukins / metabolism*
  • Leukocyte Count
  • Male
  • Mice
  • Mice, Knockout
  • Monocytes / immunology
  • Monocytes / metabolism
  • Monocytes / pathology
  • Orthomyxoviridae Infections / genetics
  • Orthomyxoviridae Infections / metabolism*
  • Orthomyxoviridae Infections / pathology
  • Orthomyxoviridae Infections / virology*
  • Permeability
  • Protein Binding
  • Staphylococcus aureus
  • Streptococcus pneumoniae
  • Superinfection*
  • Tight Junctions

Substances

  • Carrier Proteins
  • Interleukins