FIG. 1.

Effects of HIV-protease inhibitors on cultured parasites. A. Parasite morphology. Synchronized ring stage parasites were incubated with 10 μM lopinavir. Treated and control (with equivalent concentrations of DMSO) parasites were evaluated at the indicated time points on Giemsa-stained smears. B. Parasite development. Synchronized parasites were incubated with multiple concentrations of lopinavir, beginning at the ring stage. After 48 h, ring parasitemias were determined by flow cytometry analysis of YOYO-1-stained parasites, as previously described (11). Results represent two independent experiments, each performed in duplicate using the HB3 strain of P. falciparum. Error bars represent standard deviations.