Fine structure of Plasmodium berghei exoerythrocytic forms in cultured primary rat hepatocytes

Sporozoites of the rodent malaria parasite Plasmodium berghei have been grown in primary cultures of hepatocytes from Brown Norway rats. The ultrastructure of in vitro grown exoerythrocytic forms was compared with that of parasites in vivo. Peculiar vesicles, previously not described in vivo, were identified and their possible origin is discussed. Otherwise, the fine structure of the hepatocytic stages grown in vitro was shown to be grossly similar to those in vivo. Therefore, electron microscopy of cultured exoerythrocytic parasites will contribute to the understanding of the cell biology and drug sensitivity of this elusive stage.