Application of a simple culture of Plasmodium berghei for assessment of antiparasitic activity.

Mouse erythrocytes infected with Plasmodium berghei were incubated for a short period in microplate wells. The parasites changed morphologically from the immature ring form to mature schizonts, and free merozoites were released. However, reinvasion of the erythrocytes appeared not to be possible in this system. This intraerythrocytic one-step growth of the parasite could be determined quantitatively by counting incorporation of 3H-hypoxanthine. The incorporation was markedly decreased by addition of certain antiparasitic agents to the culture. The sensitivity of this growth inhibition test was comparable to or higher than the mouse protection test. The results suggested the practical utility of this simple assay in screening antimalarial activity.