The effects of C difficile toxin B, Y-27632, or PTX on CCL19-induced endocytosis by mature DCs. BC1 cells treated with LPS for 24 hours were used as mature DCs. Mature DCs were pretreated with C difficile toxin B, Y-27632, or PTX for 3 hours, then incubated with FITC-dextran (Dex) at 1 mg/mL. The amount of FITC-Dex endocytosis was determined 2 minutes after treatment. (A) Proportion of FITC-Dex–positive cells (left panel) and the MFI of the cells (right panel) following incubation; each column represents the mean ± SE of 4 independent experiments. (B) Representative fluorescence histograms from 4 independent experiments. (C) The effect of inhibitors on the viability of DCs. Following the treatment of mature BC1 cells with each inhibitor for 3 hours, the proportions of propidium iodide–negative (PI–) cells were determined; each column represents the mean ± SE of 4 independent experiments.