Dectin-1/IL-15 Pathway Affords Protection against Extrapulmonary Aspergillus fumigatus Infection by Regulating Natural Killer Cell Survival

J Innate Immun. 2023;15(1):397-411. doi: 10.1159/000527188. Epub 2023 Jan 19.

Abstract

Aspergillus fumigatus is a ubiquitous, yet potentially pathogenic, mold. The immune system employs innate receptors, such as dectin-1, to recognize fungal pathogens, but the immunological networks that afford protection are poorly explored. Here, we investigated the role of dectin-1 in anti-A. fumigatus response in an experimental model of acute invasive aspergillosis. Mice lacking dectin-1 presented enhanced signs of inflammation, with increased production of inflammatory cytokines and neutrophil infiltration, quickly succumbing to the infection. Curiously, resistance did not require T/B lymphocytes or IL-17. Instead, the main effector function of dectin-1 was the preservation of the NK cell population in the kidneys by the provision of the cytokine IL-15. While the depletion of NK cells impaired host defense in wild-type mice, IL-15 administration restored antifungal responses in dectin-1-deficient mice. Our results uncover a new effector mechanism for dectin-1 in anti-Aspergillus defense, adding an alternative approach to understand the pathophysiology of this infection.

Keywords: Aspergillus fumigatus; Dectin-1; IL-15; NK cells.

MeSH terms

  • Animals
  • Aspergillosis*
  • Aspergillus fumigatus*
  • Cytokines
  • Interleukin-15
  • Killer Cells, Natural
  • Lectins, C-Type / metabolism
  • Mice

Substances

  • dectin 1
  • Interleukin-15
  • Lectins, C-Type
  • Cytokines

Grants and funding

This work was supported by Future Medicine Education and Research Organization at Chiba University (FSYY and SS), and JSPS KAKENHI Grant number 21K07063 (SS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.