Host tissue destruction by Entamoeba histolytica: molecules mediating adhesion, cytolysis, and proteolysis.

Entamoeba histolytica, the protozoan parasite causing human amoebiasis, has recently been found to comprise two genetically distinct forms, potentially pathogenic and constitutively nonpathogenic ones. Host tissue destruction by pathogenic forms is believed to result from cell functions mediated by a lectin-type adherence receptor, a pore-forming peptide involved in host cell lysis, and abundant expression of cysteine proteinase(s). Isolation and molecular cloning of these amoeba products have provided the tools for structural analyses and manipulations of cell functions including comparisons between pathogenic and nonpathogenic forms.