IL-23 supports host defense against systemic Candida albicans infection by ensuring myeloid cell survival

PLoS Pathog. 2019 Dec 30;15(12):e1008115. doi: 10.1371/journal.ppat.1008115. eCollection 2019 Dec.

Abstract

The opportunistic fungal pathogen Candida albicans can cause invasive infections in susceptible hosts and the innate immune system, in particular myeloid cell-mediated immunity, is critical for rapid immune protection and host survival during systemic candidiasis. Using a mouse model of the human disease, we identified a novel role of IL-23 in antifungal defense. IL-23-deficient mice are highly susceptible to systemic infection with C. albicans. We found that this results from a drastic reduction in all subsets of myeloid cells in the infected kidney, which in turn leads to rapid fungal overgrowth and renal tissue injury. The loss in myeloid cells is not due to a defect in emergency myelopoiesis or the recruitment of newly generated cells to the site of infection but, rather, is a consequence of impaired survival of myeloid cells at the site of infection. In fact, the absence of a functional IL-23 pathway causes massive myeloid cell apoptosis upon C. albicans infection. Importantly, IL-23 protects myeloid cells from apoptosis independently of the IL-23-IL-17 immune axis and independently of lymphocytes and innate lymphoid cells. Instead, our results suggest that IL-23 acts in a partially autocrine but not cell-intrinsic manner within the myeloid compartment to promote host protection from systemic candidiasis. Collectively, our data highlight an unprecedented and non-canonical role of IL-23 in securing survival of myeloid cells, which is key for maintaining sufficient numbers of cells at the site of infection to ensure efficient host protection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Candida albicans / drug effects*
  • Candida albicans / immunology
  • Cell Survival / drug effects*
  • Host-Pathogen Interactions / drug effects
  • Host-Pathogen Interactions / immunology
  • Immunity, Innate / drug effects*
  • Interleukin-17 / metabolism
  • Interleukin-23 / metabolism
  • Interleukin-23 / pharmacology*
  • Lymphocytes / drug effects
  • Lymphocytes / metabolism
  • Mice, Inbred C57BL
  • Myeloid Cells / metabolism
  • Myeloid Progenitor Cells / drug effects*

Substances

  • Interleukin-17
  • Interleukin-23

Grants and funding

This study was supported by the Swiss National Science Foundation (grant #310030_166206 to SLL) and the University of Zurich. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.