Inhibition of Amebic Cysteine Proteases Blocks Amebic Trogocytosis but Not Phagocytosis

Abstract 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. Entamoeba histolytica kills by amebic trogocytosis. We show that cysteine proteases (CPs) are required for trogocytosis and cell killing but not phagocytosis. CPs inhibition decreased trogocytosis, but not phagocytosis, suggesting that CPs play a distinct role in amebic trogocytosis.