In sequential studies using animal models, E. histolytica trophozoites have been shown to adhere to the mucus layer lining the intestinal epithelium. Depletion of the mucus layer is apparently necessary for amebic penetration of the epithelial barrier. Colonic mucin also contains this glycoprotein and can inhibit the binding of Entamoeba to CHO cells. Once in contact with the epithelial barrier, the amoeba through the secretion of toxins, is able to lyse these cells and gain entry into the mucosa and are also able to kill the responding inflammatory cells.
Adherence is an absolute requirement for the initiation of cell cytotoxicity.
Factors implicated in cytotoxicity are phospholipases, proteolytic activity and pore-forming protein. A Adherence of amoeba to the intestinal mucus barrier. B Depletion of the mucus layer and disruption of the intestinal mucosa.