BACTERIUM-ASSISTED INVASION OF ENTAMOEBA-HISTOLYTICA THROUGH HUMAN ENTERIC EPITHELIA IN 2-COMPARTMENT CHAMBERS

Entamoeba histolytica trophozoites initiate amebiasis by invasion into the enteric mucosa. It is the aim of our experiments to understand ho w bacteria and leukocytes act during amebic invasion through enteric c ell layers. Cocultures were established in two-compartment chambers an d studied by measurement of transepithelial electrical resistance (TER ) and by histological examination, Trophozoites caused a decrease in T ER that was followed by formation of holes in the enteric cell layer a nd transfilter migration of trophozoites. Phagocytosed bacteria activa ted trophozoites that opened the intracellular junctions and provided access for the invasion of bacteria, Leukocytes had no effect on the d ifferent steps of invasion of the trophozoites through the human enter ic cell layers. We conclude that trophozoites, eventually assisted by enteric bacteria, disrupt enterocytic tight junctions before they open the enteric cell layer and invade through it.