title: Insights into the initiation of type 2 immune responses.
abstract: Type 2 immune responses, characterized by the differentiation of CD4+ T helper type 2 (Th2) cells and the production of the type 2 cytokines interleukin-4 (IL-4), IL-5, IL-9 and IL-13, are associated with parasitic helminth infections and inflammatory conditions such as asthma and allergies. Until recently the initiating factors associated with type 2 responses had been poorly understood. This review addresses the recent advances in identifying the diverse range of antigens/allergens associated with type 2 responses and the function, expression and sources of type-2-initiating cytokines (thymic stromal lymphopoietin, IL-25 and IL-33). We also discuss the latest findings regarding innate lymphoid cells, such as nuocytes, as early sources of type 2 cytokines and their importance in protective immunity to helminth infections. These developments represent major breakthroughs in our understanding of type 2 immunity, and highlight the increased complexity existing between the innate and adaptive arms of these responses. These additional steps in the type 2 immune pathway also offer potential targets for therapeutic intervention.
authors: MRC Laboratory of Molecular Biology, Cambridge, UK. oliphant@mrc-lmb.cam.ac.uk
authors: Chris J
authors: CJ
authors: Oliphant
authors: Jillian L
authors: JL
authors: Barlow
authors: Andrew N J
authors: AN
authors: McKenzie
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology*; D000485:Allergens / Q000276:immunology; D000818:Animals; D017951:Antigen Presentation; D000947:Antigens, Helminth / Q000276:immunology; D001249:Asthma / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007113:Immunity, Innate / Q000276:immunology*; D007378:Interleukins / Q000096:biosynthesis / Q000276:immunology*; D007962:Leukocytes; D008213:Lymphocyte Activation; D010272:Parasitic Diseases / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*; D000094632:Thymic Stromal Lymphopoietin
chemical_list: D000485:Allergens; D000947:Antigens, Helminth; D016207:Cytokines; D007378:Interleukins; D000094632:Thymic Stromal Lymphopoietin