IRF-5-Mediated Inflammation Limits CD8+ T Cell Expansion by Inducing HIF-1α and Impairing Dendritic Cell Functions during Leishmania Infection

PLoS Pathog. 2015 Jun 5;11(6):e1004938. doi: 10.1371/journal.ppat.1004938. eCollection 2015 Jun.

Abstract

Inflammation is known to be necessary for promoting, sustaining, and tuning CD8+ T cell responses. Following experimental Leishmania donovani infection, the inflammatory response is mainly induced by the transcription factor IRF-5. IRF-5 is responsible for the activation of several genes encoding key pro-inflammatory cytokines, such as IL-6 and TNF. Here, we investigate the role of IRF-5-mediated inflammation in regulating antigen-specific CD8+ T cell responses during L. donovani infection. Our data demonstrate that the inflammatory response induced by IRF-5 limits CD8+ T cell expansion and induces HIF-1α in dendritic cells. Ablation of HIF-1α in CD11c+ cells resulted into a higher frequency of short-lived effector cells (SLEC), enhanced CD8+ T cell expansion, and increased IL-12 expression by splenic DCs. Moreover, mice with a targeted depletion of HIF-1α in CD11c+ cells had a significantly lower splenic parasite burden, suggesting that induction of HIF-1α may represent an immune evasive mechanism adopted by Leishmania parasites to establish persistent infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Blotting, Western
  • CD8-Positive T-Lymphocytes / immunology*
  • Dendritic Cells / immunology*
  • Disease Models, Animal
  • Flow Cytometry
  • Hypoxia-Inducible Factor 1, alpha Subunit / biosynthesis*
  • Hypoxia-Inducible Factor 1, alpha Subunit / immunology
  • Immune Evasion / immunology*
  • Inflammation / immunology
  • Interferon Regulatory Factors / immunology*
  • Leishmania donovani
  • Leishmaniasis, Visceral / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Real-Time Polymerase Chain Reaction

Substances

  • Hif1a protein, mouse
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Interferon Regulatory Factors
  • Irf5 protein, mouse