Langerin+ DCs regulate innate IL-17 production in the oral mucosa during Candida albicans-mediated infection

PLoS Pathog. 2018 May 21;14(5):e1007069. doi: 10.1371/journal.ppat.1007069. eCollection 2018 May.

Abstract

The opportunistic fungal pathogen Candida albicans frequently causes diseases such as oropharyngeal candidiasis (OPC) in immunocompromised individuals. Although it is well appreciated that the cytokine IL-17 is crucial for protective immunity against OPC, the cellular source and the regulation of this cytokine during infection are still a matter of debate. Here, we directly visualized IL-17 production in the tongue of experimentally infected mice, thereby demonstrating that this key cytokine is expressed by three complementary subsets of CD90+ leukocytes: RAG-dependent αβ and γδ T cells, as well as RAG-independent ILCs. To determine the regulation of IL-17 production at the onset of OPC, we investigated in detail the myeloid compartment of the tongue and found a heterogeneous and dynamic mononuclear phagocyte (MNP) network in the infected tongue that consists of Zbtb46-Langerin- macrophages, Zbtb46+Langerin+ dendritic cells (DCs) and Ly6C+ inflammatory monocytes. Of those, the Langerin+ DC population stands out by its unique capacity to co-produce the cytokines IL-1β, IL-6 and IL-23, all of which promote IL-17 induction in response to C. albicans in the oral mucosa. The critical role of Langerin+ DCs for the innate IL-17 response was confirmed by depletion of this cellular subset in vivo, which compromised IL-17 induction during OPC. In conclusion, our work revealed key regulatory factors and their cellular sources of innate IL-17-dependent antifungal immunity in the oral mucosa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Surface / immunology*
  • Candida albicans / immunology*
  • Candidiasis, Oral / immunology*
  • Candidiasis, Oral / microbiology
  • Cytokines / immunology
  • Dendritic Cells / immunology*
  • Female
  • Flow Cytometry
  • Interleukin-17 / biosynthesis*
  • Interleukin-1beta / biosynthesis
  • Interleukin-23 / biosynthesis
  • Interleukin-23 / immunology
  • Interleukin-6 / biosynthesis
  • Lectins, C-Type / immunology*
  • Leukocytes / immunology
  • Male
  • Mannose-Binding Lectins / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Mononuclear Phagocyte System / immunology
  • Mouth Mucosa / cytology
  • Mouth Mucosa / immunology*
  • Mouth Mucosa / microbiology
  • Neutrophils / immunology
  • Specific Pathogen-Free Organisms
  • Spleen / cytology
  • Spleen / immunology
  • Thy-1 Antigens / immunology
  • Tongue / cytology
  • Tongue / immunology
  • Tongue / microbiology

Substances

  • Antigens, Surface
  • Cd207 protein, mouse
  • Cytokines
  • Interleukin-17
  • Interleukin-1beta
  • Interleukin-23
  • Interleukin-6
  • Lectins, C-Type
  • Mannose-Binding Lectins
  • Thy-1 Antigens