Surface localization, regulation, and biologic properties of the 96-kDa alcohol/aldehyde dehydrogenase (EhADH2) of pathogenic Entamoeba histolytica.

The 96-kDa surface antigen of Entamoeba histolytica was demonstrated through extensive immunologic evaluation with monoclonal and monospecific antibodies to be identical to or an isoform of the amebic alcohol/aldehyde dehydrogenase (EhADH2). EhADH2 was secreted, excreted, or shed into the culture medium in quantities commensurate with amebic growth when studied in a novel culture system. Of importance, using RNase protection assays, specific mRNA coding for the EhADH2 gene product(s) was up-regulated by treatment of viable trophozoites with the enzyme substrate ethanol. These data provide insight into the biology of this enzyme and its regulation by appropriate stressors.