Further Studies with Ameba-Trypanosome Cultures

Abstract

Summary Current procedures for cultivation of Entamoeba histolytica with Trypanosoma cruzi provide greater production of amebase in vitro than methods previously reported. The newer cultures lend themselves conveniently to centrifugal concentration under reduced oxygen tension. Because oxygenation is thought to be detrimental, this may enhance the vigor of amebae in inocula prepared for in vivo investigations. Despite the improved cultivation and harvesting procedures, however, E. histolytica showed decreased virulence for guinea pigs after prolonged association with T. cruzi in A-T medium in vitro. Information is presented on the growth rates of amebae in A-T cultures from measured inocula at various intervals of incubation. Considerable growth of T. cruzi occurs in A-T medium if amebae are not present, but the number of trypanosomes decreases in the presence of vigorous amebic growth. E. histolytica did not grow when species of Leishmania were substituted for T. cruzi in the A-T medium complex.