Killing of Entamoeba invadens using liposome-encapsulated drugs.

Liposomes are used as carriers of drugs intended to manipulate macrophage functions. The normal in vivo fate of liposomes is phagocytosis, followed by phospholipase-mediated disruption of their phospholipid bilayers and intracellular release of their contents. Using this method for intracellular delivery of drugs, we have developed an approach for in vivo depletion of macrophages. Phagocytosis also forms a major feature of parasitic amoebae. In the present experiments, we investigated whether amoebae could be killed using the same approach (liposome-mediated "suicide" of amoebae). The results confirm that liposomes are ingested by Ent-amoeba invadens cultured under routine laboratory conditions. From various chelator molecules and their metalion complexes that were active in the liposome-mediated elimination of macrophages, Cu-ethylenediaminetetraacetic acid (EDTA) complexes appeared to be the most efficacious compounds in the elimination of E. invadens.