In vitro culture and drug sensitivity assay of Plasmodium falciparum with nonserum substitute and acute-phase sera

The short-term in vitro growth of Plasmodium falciparum parasites in the as exual erythrocytic stage and the in vitro activities of eight standard anti malarial drugs were assessed and compared by using RPMI 1640 medium supplem ented with 10% nonimmune human serum, 10% autologous or homologous acute-ph ase serum, or 0.5% Albumax I (lipid-enriched bovine serum albumin), In gene ral, parasite growth was maximal with autologous (or homologous) serum, fol low ed by Albumax I and nonimmune serum. The 50% inhibitory concentrations (IC(50)s) varied widely, depending on the serum or serum substitute. The co mparison of IC(50)s between assays with autologous and nonimmune sera showe d that monodesethylamodiaquine. halofantrine, pyrimethamine, and cycloguani l had similar IC(50)s, Although the IC(50)s of chloroquine, monodesethylamo diaquine, and dihydroartemisinin were similar with Albumax I and autologous sera, the IC(50)s of all test compounds obtained with Albumax I differed c onsiderably from the corresponding values obtained with nonimmune serum. Ou r results suggest that Albumax I and autologous and homologous sera from sy mptomatic, malaria-infected patients mag be useful alternative sources of s erum for in vitro culture of P. falciparum isolates in the field. However. autologous sera and Albumax I do not seem to be suitable for the standardiz ation of isotopic in vitro assays for all antimalarial drugs.