title: Nuocytes: expanding the innate cell repertoire in type-2 immunity.
abstract: Activation and differentiation of the Th1 cell population lead to their production of the classical type-1 cytokines IFN-γ, IL-2, and TNF-β, thus promoting type-1 immunity. This is thought to occur via the ligation of TLRs by bacterial and viral products, which in turn, drive production of the essential Th1 cell differentiation factor, IL-12, by dendritic cells (DCs). Concurrent studies have been able to identify the effector cytokines produced by Th2 cells (IL-4, IL-5, IL-9, and IL-13) as being essential for parasitic immunity and also as essential factors in allergic asthma. However, the factors that are critical for initiation of the type-2 response remained obscure. Recently however, two critical observations have led to a more detailed understanding of the innate type-2 response. First, two novel, type-2-inducing cytokines-IL-25 and IL-33-were identified as being necessary for the up-regulation of the type-2 effector cytokines, mirroring the role of IL-12 in the type-1 response. Second, studies focused on target cell populations of IL-25 and IL-33 have identified novel, innate cell populations, which potentially bridge the gap between presentation of the type-2-inducing cytokine and the later adaptive Th2 cell response. In this review, we will discuss these new type-2 innate cell populations, in particular, the recently discovered nuocyte population, which are required for type-2 responses against helminthic parasites.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, United Kingdom. jbarlow@mrc-lmb.cam.ac.uk
authors.forename: Jillian L
authors.initials: JL
authors.lastname: Barlow
authors.forename: Andrew N J
authors.initials: AN
authors.lastname: McKenzie
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000145:classification / Q000166:cytology / Q000276:immunology; D000947:Antigens, Helminth / Q000276:immunology; D006373:Helminthiasis / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D020381:Interleukin-17 / Q000276:immunology* / Q000378:metabolism; D000067596:Interleukin-33; D007378:Interleukins / Q000276:immunology* / Q000378:metabolism; D008233:Lymphotoxin-alpha / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
chemical_list: D000947:Antigens, Helminth; C486701:IL25 protein, human; C506536:IL33 protein, human; D020381:Interleukin-17; D000067596:Interleukin-33; D007378:Interleukins; D008233:Lymphotoxin-alpha