title: IL-21 reduces immediate hypersensitivity reactions in mouse skin by suppressing mast cell activation or IgE production.
abstract: IL-21 regulates activation, proliferation, and differentiation of various immune cells. We have previously shown that exogenous IL-21 administration reduces allergic reactions in mouse models of anaphylaxis and allergic rhinitis. However, the effects of IL-21 in allergic cutaneous reactions remain unclear. In this study, we examined the effects of IL-21 in a mouse model of the IgE-mediated cutaneous immediate hypersensitivity reaction (IHR). We also investigated the mechanism of IL-21-induced regulation of allergic cutaneous reactions. Mice were sensitized by intraperitoneal ovalbumin (OVA) injection and challenged by injecting OVA intradermally into the ears, with intraperitoneal administration of recombinant murine (rm)IL-21 during the sensitization period or after completion of sensitization. After challenge, IL-21-untreated allergic mice developed biphasic responses characterized by early-phase and late-phase reactions. The biphasic reactions were significantly reduced by rmIL-21 treatment during sensitization or after completion of sensitization. Administration of rmIL-21 during sensitization reduced the cutaneous IHR by suppressing allergen-specific IgE production. In contrast, administration of rmIL-21 after completion of sensitization did not decrease serum levels of allergen-specific IgE, but significantly suppressed mast cell degranulation in skin. These results suggest that the regulatory effects of IL-21 on the cutaneous IHR involve suppression of allergen-specific IgE production or mast cell degranulation.
authors: Department of Dermatology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto, Japan. risat@koto.kpu-m.ac.jp
authors: Risa
authors: R
authors: Tamagawa-Mineoka
authors: Tsunao
authors: T
authors: Kishida
authors: Osam
authors: O
authors: Mazda
authors: Norito
authors: N
authors: Katoh
mesh_terms: D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D006636:Histamine Release / Q000187:drug effects; D006969:Hypersensitivity, Immediate / Q000517:prevention & control*; D007073:Immunoglobulin E / Q000096:biosynthesis*; D007378:Interleukins / Q000032:analysis / Q000494:pharmacology*; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D012867:Skin / Q000276:immunology* / Q000473:pathology; D000098546:Interleukin-21
chemical_list: D007378:Interleukins; D007073:Immunoglobulin E; D000098546:Interleukin-21