| Summary: | 碩士 === 國立臺灣大學 === 醫學檢驗暨生物技術學研究所 === 100 === Allergic airway disease is a chronic inflammation, which is regarded as Th2 weighted imbalance. After allergens or parasitic helminthes stimulation, the phenomena of eosinophil increase, mast cell activation, immunoglobulin E (IgE) antibody production and cytokines such as interleukin (IL)–4, IL-5, and IL-13 secreted by Th2 cells are contributed to allergic disease. Previous study suggests that IL-21 administration into the nostril alleviates murine allergic rhinitis by means of reducing the production of IgE. However, whether IL-21 affects Th2 cells is still unknown. In this study, we investigated the role of IL-21 in the regulation of Th2 cell differentiation and Th2 immune responses in vitro and in vivo.
First, we explored whether IL-21 affects the Th2 cell differentiation. The secretion of IL-4 from DO11.10 CD4 T cells which were cultured with different concentration of IL-21 under Th2 polarizing condition was decreased. In addition, we confirmed that the decreased level of IL-4 was not caused by IL-21-inducing apoptosis of cells. Furthermore, we also observed the significantly decreased level of Th2-associated cytokines in the BALF of OVA/Alumimmunized mice which were received Ad-mIL-21 before OVA immunization. Besides, the administration of Ad-mIL-21 reduced IL-4 production in the BALF of OVA/Alum immunized mice. Furthermore, IL-21 administration decreased the expression of transcription factor GATA3 of T cells.
In conclusion, our results demonstrated that IL-21 decreased the Th2 cell differentiation and Th2 immune response. Moreover, the effects of IL-21 in the down regulation of Th2 cells were resulted in the down-regulation of GATA3 but not the apoptosis of Th2-producing cells.
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