title: IL-17 is necessary for host protection against acute-phase Trypanosoma cruzi infection.
abstract: IL-17A is a key cytokine that induces inflammatory responses through the organized production of inflammatory cytokines, such as IL-6, TNF-alpha, and GM-CSF, and induces neutrophil migration. The roles of IL-17A in infection of intracellular protozoan parasites have not been elucidated, although augmented immune responses by IL-17A are important for the resolution of some bacterial and fungal infections. Therefore, we experimentally infected IL-17A-deficient (IL-17A(-/-)) mice with Trypanosoma cruzi. IL-17A(-/-) mice had a lower survival rate and prolonged worse parasitemia compared with control C57BL/6 wild-type (WT) mice postinfection. In the infected IL-17A(-/-) mice, multiple organ failure was observed compared with WT mice, as reflected by the marked increase in serologic markers of tissue injury, such as aspartate aminotransferase, which resulted in increased mortality of IL-17A(-/-) mice. Expression of cytokines, such as IFN-gamma, IL-6, and TNF-alpha, was lower in liver-infiltrating cells from the IL-17A(-/-) mice compared with WT mice. A similar defect was observed in the expression of neutrophil enzymes, such as myeloperoxidase and lipoxygenase, whereas cellular infiltration into the infected tissues was not affected by IL-17A deficiency. These results suggested that the efficient activation of immune-related cells critical for the killing of T. cruzi was impaired in the absence of IL-17A, resulting in the greater susceptibility of those mice to T. cruzi infection. From these results, we conclude that IL-17A is important for the resolution of T. cruzi infection.
authors.affiliation: Division of Molecular and Cellular Immunoscience, Department of Biomolecular Sciences, Saga University, Saga, Japan. miyazak4@cc.saga-u.ac.jp
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Hamano
authors.forename: Seng
authors.initials: S
authors.lastname: Wang
authors.forename: Yohei
authors.initials: Y
authors.lastname: Shimanoe
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yoshida
mesh_terms: D000210:Acute-Phase Reaction / Q000276:immunology* / Q000469:parasitology; D000818:Animals; D002478:Cells, Cultured; D014355:Chagas Disease / Q000276:immunology* / Q000469:parasitology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D020381:Interleukin-17 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008099:Liver / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009102:Multiple Organ Failure / Q000235:genetics / Q000276:immunology / Q000469:parasitology; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D018512:Parasitemia / Q000276:immunology / Q000401:mortality; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha