Role of the galactose lectin of Entamoeba histolytica in adherence-dependent killing of mammalian cells. Infect. Immun

Entamoeba histolytica extraceliular killing of host cells is contact dependent. Adherence to human colonic epithelial cells and mucins is mediated by a galactose-specific lectin. The effect on cytotoxicity of a panel of monoclonal antibodies (MAb) directed against the galactose lectin was tested. As expected, those MAb which inhibited adherence also decreased cytotoxicity. However, one antilectin MAb blocked cytotoxicity after adherence had occurred, indicating that the lectin has a role in cell killing that is distinct from its adherence function. En_tamoeba histolytica is a cytolytic protozoan parasite that is responsible for an estimated 100,000 deaths per year from amebic liver abscess and colitis. The initial steps in pathogenesis include adherence to colonic mucosa, subse-quent lysis of the mucosal surface, and invasion through the colonic epithelium. The events leading to host cell destruc-tion following adherence are unknown. The purpose of this study was to analyze the role of the galactose-specific lectin of E. histolytica in the killing of target cells