Proteinase activity & virulence of Entamoeba histolytica on passage through hamster liver.

This study was undertaken to determine the enzymatic differences in the process of increasing the degree of virulence in E. histolytica successively passaged in hamster liver. Substrate gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of one axenic E. histolytica (strain HM1:IMSS) and five xenic isolates of the same strain of E. histolytica passaged five times through hamster liver. Trophozoites successively passaged in hamster liver showed in supernatants, major bands in the 56-97 kDa region whereas only the axenic strain produced additional band at 34 KDa. Inoculation of amoebic trophozoites into hamster led to progressive increase in proteinase activity of supernatants as well as increased virulence of amoebae; proteinase activity of amoebae showed an excellent correlation with their virulence. All the infected animals died when activity of proteinase was 0.152 mg of protein.