E. histolytica rapidly triggers apoptosis in a cecal epithelial cells in vitro. CBA Immortomouse cecal epithelial cells were grown to confluence and co-incubated with E. histolytica trophozoites. A: AnnexinV binding was assessed at 0 minutes (no amoeba, red line), 30 minutes (purple line), and 60 minutes (blue line). Data are shown from one representative experiment of three. B: Apoptotic DNA fragmentation was determined in cecal epithelial cells by using ELISA as described in Materials and Methods at 0- to 90-minute time points. Results are combined data from two independent experiments. *P < 0.05. C: Changes in mitochondrial membrane potential (ΔΨ) were determined by staining epithelial cells with a mitochondrial vital dye as described in Materials and Methods at 0, 20, and 60 minutes. Disruption of normal mitochondrial function results in decreased accumulation of dye and reduced fluorescence intensity from 90.3% to 72.7%. Data are shown from one representative experiment of two.