Inhibition of Amebic Cysteine Proteases Blocks Amebic Trogocytosis but Not Phagocytosis

Background. Entamoeba histolytica kills human cells by ingesting fragments of live cells until the cell eventually dies, a process termed amebic trogocytosis. In a previous study, we showed that acidified amebic lysosomes are required for both amebic trogocytosis and phagocytosis, as well as cell killing. Methods. Amebic cysteine proteases (CPs) were inhibited using an irreversible inhibitor, E-64d. Results. Interfering with amebic CPs decreased amebic trogocytosis and amebic cytotoxicity but did not impair phagocytosis. Conclusions. We show that amebic CPs are required for amebic trogocytosis and cell killing but not phagocytosis. These data suggest that amebic CPs play a distinct role in amebic trogocytosis and cell killing.