Cloning of a fresh isolate of Plasmodium falciparum and drug sensitivity of the clones.
A freshly isolated strain of Plasmodium falciparum was cloned by limited dilution using a co-culture of infected erythrocytes on monolayers of functionally active rodent hepatocytes. 15 clones were isolated, and the anti-malarial activity of chloroquine, quinine, mefloquine and halofantrine against the clones, the original isolate, and a culture-adapted isolate was determined using a 48 h radioisotope microdilution method. The multiplication rates of all clones and the culture-adapted isolate were estimated by counting the number of parasitized cells on Giemsa-stained thin smears. Variations found in drug sensitivity and multiplication rate of different clones provided strong evidence of heterogeneity of a single strain parasite population. No morphological variation was detected by light microscopy. The use of a hepatocyte feeder layer improved the adaptation of cloned parasites to continuous culture conditions and thus enabled us to clone directly a fresh isolate, without losing clones during the culture-adaptation process.
Mirovsky
P
P
Département de Parasitologie, Médecine Tropicale et Santé Publique, INSERM U313, Groupe Hospitalier Pitié-Salpetriex, Paris, France.
Gay
F
F
Bustos
D
D
Mazier
D
D
Gentilini
M
M
D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D002999:Clone Cells / Q000166:cytology / Q000187:drug effects; D015925:Cryopreservation; D008099:Liver / Q000166:cytology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000254:growth & development*; D013997:Time Factors
D000962:Antimalarials