Improved techniques for the culture of the liver stages of Plasmodium berghei and their relevance to the study of causal prophylactic drugs.

The in vitro exoerythrocytic (EE) of Plasmodium berghei was compared in primary rat and mouse hepatocytes and the human hepatoma cell line HepG2. All of the cell-types supported the full maturation of EE stages, but the HepG2 cells were much more susceptible to infection than the primary rodent hepatocytes and were also the most efficient host cells. Following refinement of culture techniques, the development of EE forms which is now observed in HepG2 cells closely reflects that occurring in vivo with respect to the morphology and size of parasites and their rate of maturation. Furthermore, high densities of parasites are reproducibly achieved. A detailed description is presented of exoerythrocytic development in HepG2 cells. The application of these cultures to chemosensitivity studies is discussed and the relative advantages of employing cell lines or primary hepatocytes as host cells in such a system are considered.