Murine Th9 cell-mediated allergic inflammation shows different steroid responsiveness depending on target organs

Abstract

Abstract Th9 cell has been implicated in the development of allergic inflammation, though the sensitivity of Th9 cell-mediated responses to steroid therapy remains unclear. Here, allergen-induced bronchial and nasal inflammatory responses and their steroid responsiveness were comparatively investigated in ovalbumin (OVA)-specific Th9 cell-transferred mice. BALB/c mice were transferred with in vitro-differentiated Th9 cells and challenged by intratracheal or intranasal injection of OVA. The significant nasal hyperresponsiveness accompanied by nasal infiltration of eosinophils as well as allergen-specific T cells was induced in Th9 cell-transferred mice upon intranasal allergen challenge. These responses were strongly suppressed by the treatment with dexamethasone. Substantial accumulation of eosinophils in the lungs and bronchial hyperresponsiveness (BHR) were induced by intratracheal OVA challenge. In contrast with the nasal responses, neither cellular infiltration in the lungs nor BHR in Th9 cell-transferred mice was affected by dexamethasone treatment. In addition to the possible contribution of Th9 cells to the development of allergic inflammation in various tissues, different steroid responsiveness of Th9 cell-mediated responses among target organs was suggested.