METHODS: Cultured Normal Human bronchial epithelial (NHBE) cells and human basophil cell line KU812 cells were used to study the epithelial cell-basophil interactions in the house dust mite (HDM)-induced production of IL-5. Production of IL-5, IL-33 and sST2 was evaluated by ELISA.
RESULTS: HDM stimulated the rapid release of IL-33 from cultured NHBE cells at 1 hour after the incubation. Basophil cell line KU812 cells produced IL-5 in response to IL-33, and the conditioned medium of HDM-stimulated NHBE cells stimulated IL-5 production from KU812 cells. Co-culture of NHBE cells with KU812 cells stimulated the production of sST2 time-dependently in response to HDM, and HDM did not stimulate the production of IL-5 in co-cultured cells.
CONCLUSIONS: These results indicate that epithelial cell-derived IL-33 stimulates the production of IL-5 from basophils, and sST2 is an important regulator of IL-33 in innate allergic inflammation.