Extracellular development of erythrocytic stages ofPlasmodium falciparum

Abstract

Continuous culture of the erythrocytic cycle of Plasmodium falciparum within human erythrocytes maintained under appropriate conditions in vitro has facilitated a large body of fundamental investigations with this important pathogen. It has revealed complex relationships between the developing intracellular parasite and its host erythrocyte. In pursuit of further understanding of these relationships, we have now developed,.and here describe, methods that support extracellular development of the erythrocytic stages of P falciparum.Since only 1 to 2% of an inoculum of free merozoites can develop extracellularly through the entire schizogonic cycle to again form merozoites, the method does not support continuous extracellular culture. The work shows that the parasitophorous membrane and vacuole are not essential. Development of the parasites beyond the ring stage does however require constituents of the erythrocyte membrane.Abbreviations: CPD = citrate-phosphate dextrose; KIS = KI medium with 10% human serum; RP-C = RP medium without bicarbonate or serum; RPS = RP medium with bicarbonate and serum

Contributions of cell culture to the investigation and control of infectious diseases

“…Although many intracellular protozoans have been propagated in vitro, one of the greatest challenges is the axenic (without host cell) propagation of these forms in order to better understand the cellular and molecular aspects of their host-parasite relationship. Featured in this special section is an article by Trager et al describing a method for the axenic growth of the merozoite form of the malarial parasite, Plasmodium falciparum [60]. A final challenge is the growth of helminths in vitro.…”

Preparation of pure and intact Plasmodium falciparum plasma membrane vesicles and partial characterisation of the plasma membrane ATPase

“…Although extracellular, axenic development of the erythrocyte cycle of P. falciparum has been obtained [2-4], the number of merozoites completing the cycle is not sufficient to permit continuous extracellular culture. Under the best conditions, only 1% of the merozoites further develops into trophozoites.…”