title: Group 2 innate lymphoid cells facilitate sensitization to local, but not systemic, TH2-inducing allergen exposures.
abstract: BACKGROUND
  Allergic inflammation involves the sensitization of naive CD4(+) T cells to allergens, resulting in a TH2-skewed inflammatory response. Although antigen presentation by dendritic cells to T cells in the lymph node is crucial for TH2 cell development, the innate signals that initiate adaptive type 2 inflammation and the role of group 2 innate lymphoid cells (ILC2s) are poorly understood.
  
  
  OBJECTIVE
  We sought to investigate the influence of ILC2s and the route of priming on the development of an adaptive type 2 immune response to lung allergens.
  
  
  METHODS
  Wild-type and ILC2-deficient mice were exposed intranasally or systemically to the TH2-inducing antigens house dust mite or ovalbumin in a model of allergic airway inflammation or the TH17-inducing bacterial antigen Saccharopolyspora rectivirgula in a model of hypersensitivity pneumonitis. The formation of an adaptive immune response was evaluated based on serum antibody titers and production of T cell-derived cytokines (IL-4, IL-5, IL-13 and IL-17A).
  
  
  RESULTS
  We find that lung ILC2s play a critical role in priming the adaptive type 2 immune response to inhaled allergens, including the recruitment of eosinophils, TH2 cytokine production and serum IgE levels. Surprisingly, systemic priming with ovalbumin, with or without adjuvants, circumvents the requirement for ILC2s in inducing TH2-driven lung inflammation. ILC2s were also found to be dispensable for the sensitization to TH1- or TH17-inducing antigens.
  
  
  CONCLUSIONS
  These data highlight a critical role for ILC2s in the development of adaptive type 2 responses to local, but not systemic, antigen exposure.
authors.affiliation: The Biomedical Research Centre, University of British Columbia, Vancouver.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gold
authors.affiliation: The Biomedical Research Centre, University of British Columbia, Vancouver.
authors.forename: Frann
authors.initials: F
authors.lastname: Antignano
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver.
authors.forename: Timotheus Y F
authors.initials: TY
authors.lastname: Halim
authors.affiliation: UBC James Hogg Research Centre, St Paul's Hospital, Vancouver.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Hirota
authors.affiliation: Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Quebec City.
authors.forename: Marie-Renee
authors.initials: MR
authors.lastname: Blanchet
authors.affiliation: The Biomedical Research Centre, University of British Columbia, Vancouver; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver.
authors.forename: Colby
authors.initials: C
authors.lastname: Zaph
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver.
authors.forename: Fumio
authors.initials: F
authors.lastname: Takei
authors.affiliation: The Biomedical Research Centre, University of British Columbia, Vancouver. Electronic address: kelly@brc.ubc.ca.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McNagny
mesh_terms: D056704:Adaptive Immunity; D000485:Allergens / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D007113:Immunity, Innate; D015848:Interleukin-5 / Q000096:biosynthesis; D008168:Lung / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D016131:Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D039981:Pyroglyphidae / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
chemical_list: D000485:Allergens; D015848:Interleukin-5
keywords: IgE; Innate lymphocytes; T(H)2; allergy; asthma; house dust mite