| 研究実績の概要 |
IL-33, known as an “alarmin”, has shown protective effects against infections with some pathogens in various organs, however, its contribution to antiviral host defense in skin remains to be defined. Here, we found that, in herpes simplex virus (HSV)-2-infected murine skin, IL-33 protein kinetics paralleled the kinetics of HSV titer, suggesting that productive viral replication promotes IL-33 release in skin. Ex vivo mast cell (MC) activation analysis demonstrated that supernatants of HSV-2-infected epidermis of wild type (WT) mice, but not IL-33-/- mice, induced TNF-αproduction by bone marrow-derived MCs (BMMCs), indicating that IL-33 released from HSV-2-infected epidermis activates BMMCs. Moreover, ST2-/- mice exhibited increased clinical severity and mortality following cutaneous HSV-2 infection. To see whether IL-33/ST2 signaling on MCs contributes to antiviral host defense, bone marrow-derived mast cells (BMMCs) generated from WT or ST2-/- mice were reconstituted in the skin of MCs deficient (W/Wv) mice before HSV-2 infection. We found that intradermal reconstitution with WT-BMMCs, but not ST2-/- BMMCs, significantly restored the clinical severity and mortality in HSV-2-infected W/Wv mice, indicating the importance of IL-33/ST2 axis on MCs in host defense. Thus, IL-33 derived from epidermis damaged by HSV infection has a critical role in triggering MC-mediated antiviral responses.
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