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 tis sue destruction by pathogenic forms is believed to result from cell fu nctions mediaed by a lectin-type adherence receptor, a pore-forming pe ptide involved in host cell lysis, and abundant expression of cysteine proteinase(s). Isolation and molecular cloning of these amoeba produc ts have provided the tools for structural analyses and manipulations o f cell functions including comparisons between pathogenic and nonpatho genic forms.