The Il9 CNS-25 Regulatory Element Controls Mast Cell and Basophil IL-9 Production

IL-9 is an important mediator of allergic disease that is critical for mast cell–driven diseases. IL-9 is produced by many cell types, including T cells, basophils, and mast cells. Yet, how IL-9 is regulated in mast cells or basophils is not well characterized. In this report, we tested the effects of deficiency of a mouse Il9 gene regulatory element (Il9 CNS-25) in these cells in vivo and in vitro. In mast cells stimulated with IL-3 and IL-33,...