Improvement of growth of Plasmodium falciparum fresh clinical isolates by using an established serum-free medium, GIT.

In the present study, we have tried to establish continuous cultures of fresh clinical isolates of P. falciparum by using a serum-free medium, GIT. To examine the ability of GIT to support the parasite growth, the growth of various P. falciparum isolates including two laboratory strains of P. falciparum, FCR3 and K1 was compared in both of GIT and RPMI 1640 medium supplemented by 10% human serum (RPMI-HS). Growth rates of various P. falciparum expressed as fold increases were compared in GIT and RPMI-HS, and the maximum growth rates of P. falciparum were 72 in GIT and 35 in RPMI-HS during the culture for 8 days. Growth rate of the clinical isolates varied individually in both culture media, with average growth rates of parasites being 15.9 in GIT and 8.8 in RPMI-HS, respectively (not significant). Growth rates of FCR3 and K1 strains were 28.0 and 6.6 in GIT, and 10 and 7.5 in RPMI-HS. After 30 days culture of P. falciparum in GIT, 9 of 12 clinical isolates still continuously propagated but other three isolates disappeared. Despite variation of the P. falciparum isolates in their abilities to multiply in GIT, our experiments suggested that GIT is useful for culture of fresh clinical isolates of P. falciparum that are derived from geographically distinct areas as well as laboratory strains used commonly in laboratory research.