Time kinetic and dose response analysis of the IL-4–induced development of MCTChigh. HCMCs grown in the presence of SCF (100 ng/mL) and IL-6 (80 ng/mL) for 10 weeks (defined as day 0 mast cells) were further cultured with (closed circle) or without (open circle) IL-4 (10 ng/mL) in the presence of SCF and IL-6. In some experiments, IL-4 was withdrawn (open triangle) after 21-day culture with IL-4. In time kinetic analysis (a) the cells were cytocentrifuged after indicated periods of culture, and chymase was detected immunocytochemically with MoAb specific for human chymase. IL-4–treated mast cells showed statistically significant increased number of MCTChigh compared with IL-4–nontreated mast cells (*P < .05, **P < .01, ***P < .001). In dose-response analysis (b), 10-week cultured HCMCs were cultured with various concentrations of IL-4 for 21 days and then chymase was detected immunocytochemically (***P < .001). At least 500 cells were counted in each sample under a microscope. The data shown are the mean of three independent experiments.
