IL-17RA signaling reduces inflammation and mortality during Trypanosoma cruzi infection by recruiting suppressive IL-10-producing neutrophils

PLoS Pathog. 2012;8(4):e1002658. doi: 10.1371/journal.ppat.1002658. Epub 2012 Apr 26.

Abstract

Members of the IL-17 cytokine family play an important role in protection against pathogens through the induction of different effector mechanisms. We determined that IL-17A, IL-17E and IL-17F are produced during the acute phase of T. cruzi infection. Using IL-17RA knockout (KO) mice, we demonstrate that IL-17RA, the common receptor subunit for many IL-17 family members, is required for host resistance during T. cruzi infection. Furthermore, infected IL-17RA KO mice that lack of response to several IL-17 cytokines showed amplified inflammatory responses with exuberant IFN-γ and TNF production that promoted hepatic damage and mortality. Absence of IL-17RA during T. cruzi infection resulted in reduced CXCL1 and CXCL2 expression in spleen and liver and limited neutrophil recruitment. T. cruzi-stimulated neutrophils secreted IL-10 and showed an IL-10-dependent suppressive phenotype in vitro inhibiting T-cell proliferation and IFN-γ production. Specific depletion of Ly-6G+ neutrophils in vivo during T. cruzi infection raised parasitemia and serum IFN-γ concentration and resulted in increased liver pathology in WT mice and overwhelming wasting disease in IL-17RA KO mice. Adoptively transferred neutrophils were unable to migrate to tissues and to restore resistant phenotype in infected IL-17RA KO mice but migrated to spleen and liver of infected WT mice and downregulated IFN-γ production and increased survival in an IL-10 dependent manner. Our results underscore the role of IL-17RA in the modulation of IFN-γ-mediated inflammatory responses during infections and uncover a previously unrecognized regulatory mechanism that involves the IL-17RA-mediated recruitment of suppressive IL-10-producing neutrophils.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Chagas Disease / immunology*
  • Inflammation / immunology
  • Interferon-gamma / immunology
  • Interleukin-10 / biosynthesis
  • Interleukin-10 / immunology
  • Interleukin-17 / immunology
  • Liver / immunology
  • Liver / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neutrophil Infiltration
  • Neutrophils / immunology*
  • Neutrophils / metabolism
  • Receptors, Interleukin-17 / immunology*
  • Signal Transduction*
  • Spleen / immunology
  • Spleen / metabolism
  • Trypanosoma cruzi / immunology*

Substances

  • IL10 protein, mouse
  • Il17ra protein, mouse
  • Interleukin-17
  • Receptors, Interleukin-17
  • Interleukin-10
  • Interferon-gamma