title: Concurrent bacterial stimulation alters the function of helminth-activated dendritic cells, resulting in IL-17 induction.
abstract: Infection with schistosome helminths is associated with granulomatous inflammation that forms around parasite eggs trapped in host tissues. In severe cases, the resulting fibrosis can lead to organ failure, portal hypertension, and fatal bleeding. Murine studies identified IL-17 as a critical mediator of this immunopathology, and mouse strains that produce high levels of IL-17 in response to schistosome infection show increased mortality. In this article, we demonstrate that schistosome-specific IL-17 induction by dendritic cells from low-pathology C57BL/6 mice is normally regulated by their concomitant induction of IL-10. Simultaneous stimulation of schistosome-exposed C57BL/6 dendritic cells with a heat-killed bacterium enabled these cells to overcome IL-10 regulation and induce IL-17, even in wild-type C57BL/6 recipients. This schistosome-specific IL-17 was dependent on IL-6 production by the copulsed dendritic cells. Coimmunization of C57BL/6 animals with bacterial and schistosome Ags also resulted in schistosome-specific IL-17, and this response was enhanced in the absence of IL-10-mediated immune regulation. Together, our data suggest that the balance of pro- and anti-inflammatory cytokines that determines the severity of pathology during schistosome infection can be influenced not only by host and parasite, but also by concurrent bacterial stimulation.
authors.affiliation: Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom. gperona@mail.ubc.ca
authors.forename: Georgia
authors.initials: G
authors.lastname: Perona-Wright
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Lundie
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Jenkins
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Webb
authors.forename: Richard K
authors.initials: RK
authors.lastname: Grencis
authors.forename: Andrew S
authors.initials: AS
authors.lastname: MacDonald
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000947:Antigens, Helminth / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D016753:Interleukin-10 / Q000378:metabolism / Q000502:physiology; D020381:Interleukin-17 / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011425:Propionibacterium acnes / Q000276:immunology*; D012550:Schistosoma mansoni / Q000276:immunology; D012552:Schistosomiasis / Q000276:immunology / Q000378:metabolism / Q000473:pathology
chemical_list: D000947:Antigens, Helminth; D020381:Interleukin-17; D016753:Interleukin-10