Dasatinib inhibits IgE-dependent production/secretion of IL-4 in mouse basophils. (A) Cultured mouse basophils preincubated with TNP-specific IgE, were exposed to control medium (containing DMSO) or to TNP (3 μg/mL) in the presence or absence of dasatinib (1 μM) as indicated, for 24 hours. Then, cells were centrifuged and the cell-free supernatants recovered and examined for the content of IL-4 by ELISA. Panel A shows a typical experiment performed with impure cells. Results representing the means (± SD) from triplicates. (B) Enriched sorted basophils stained with Wright-Giemsa stain. Acquisition of figures was performed by an Olympus DP11 camera connected to an Olympus BX50F4 microscope equipped with 100×/1.35 UPlan-Apo objective lenses (Olympus, Hamburg, Germany). Images were processed with Adobe Photoshop software version 7.0 (Adobe Systems, San Jose, CA). Magnification ×100. (C) Flow cytometric detection of the IgE receptor on enriched basophils using IgE and an anti-IgE antibody. As visible, the purity of IgE receptor–positive basophils amounted to more than 70%. (D) Effects of dasatinib on IL-4 production/secretion in sorted mouse basophils (conditions as in A). Results represent the means (± SD) from triplicates.