Identification of stocks of non-pathogenic "Entamoeba histolytica"

The isoenzyme mobilities, on thin layer starch gel electrophoresis, of stocks of Entamoeba histolytica have been shown to relate to pathogenicity in the host. The ability of some zymodemes of this organism to produce extra-intestinal lesions is also coupled with a capacity to resist lysis by human serum. The results of isoenzyme characterization particularly related to serum lysis is discussed.