Fine structural changes at Entamoeba histolytica rabbit kidney cell (RK 13) interface.

When bacteria-free trophozoites of Entamoeba histolytica were added to a monolayer of rabbit kidney cells, cellular injury occurred at the sites of contact. Changes appeared within the cell cytoplasm before there was any generalized cell membrane damage. At some points of contact there was apparent fusion of amoebic and cell cytoplasm. Electron-dense bodies, here interpreted as liposomes, were present in the amoebic cytoplasm and beneath the surface membrane. No surface lysosomes were seen. Various modes of cell damage and enzyme transfer from amoeba to cell are suggested, together with the possibility that cytopathic amoebae are infected with virus particles.