Crucial role of stimulator of interferon genes-dependent signaling in house dust mite extract-induced IgE production

Stimulator of interferon genes (STING) is a DNA sensor that responds to pathogens and induces type I interferon production. Herein, the role of STING in house dust mite extract (HDM)-induced allergic asthma was investigated. C57BL/6 wild-type (WT) and Sting −/− mice were intratracheally sensitized with HDM, and the bronchoalveolar lavage fluid (BALF), sera, lungs, and mediastinal lymph nodes (MLNs) were analyzed. The total and HDM-specific serum IgE levels were lower in Sting −/− mice than in WT mice. B cell and IgE-positive B cell proportion in BALF and MLNs, respectively, was significantly lower in Sting −/− mice than in WT mice. Additionally, cyclic GMP-AMP, a STING ligand, augmented total and HDM-specific serum IgE levels and B cell proportion in BALF when applied in combination with HDM. To elucidate the role of STING in IgE production, follicular helper T (Tfh) cells, which are involved in B cell maturation, were investigated. Tfh cell proportion in MLNs decreased in Sting −/− mice, and IL-4 and IL-13 production by HDM-restimulated MLN cells from HDM-sensitized mice was decreased in Sting −/− mice compared with WT mice. Thus, STING plays an important role in the maturation and class switching of IgE-producing B cells in allergic inflammation via Tfh cells.