UPTAKE OF CHLOROQUINE-3-H³ BY PLASMODIUM KNOWLESI IN VITRO

¹ Department of Hematology, Walter Reed Army Institute of Research, Washington, D.C.

Certain aspects of chloroquine-3-H³ (CQ-3-H³) uptake by Plasmodium knowlesi were investigated in vitro. CQ-3-H³ uptake had a biphasic time course: an initial rapid uptake followed by a slow increase to a saturation value reached after three hours. CQ-3-H³ uptake was reduced in the presence of metabolic inhibitors, in the absence of glucose and at low temperature. Intra-and extracellular CQ-3-H³ appeared to be in a dynamic equilibrium in which dihydroquinine and quinacrine could participate. The characteristics of CQ-3-H³ uptake by plasmodia resembled uptake of albumin by mammalian cells. Pinocytosis, with subsequent accumulation in lysosomes, is proposed as the mechanism of CQ-3-H³ uptake by plasmodia.