E. histolytica-derived secretory products (SPs) of pathogenic amoebae do not induce cell death or exocytosis in mast cells. (A) Percentage of CD63-positive cells in HMC-1 cells incubated with SPs or platelet-activating factor (PAF) (5 μM). (n = 3) (B) Percentage of CD63-positive cells in bone marrow-derived murine mast cells incubated with SPs, phorbol 12-myristate 13-acetate (PMA) (50nM) or DNP-HSA (250 ng/mL). (n = 4). (C) Flow cytometry analysis of HMC-1 cell death after stimulation with or without SPs. (n = 4). All reactions were performed in triplicate measurements of each experiment. All data are presented as the mean ± SEM of at least three independent experiments. The asterisks indicate the results of comparisons with the controls (**p < 0.01).