Figure 4

ΔFd causes selective haemolysis of parasitized red cells leading to anomalous egress of trophozoites. (A) Samples of mixed stage parasite culture at different parasitaemia (P) (% figures on respective curves) were incubated (3 hr) with the indicated concentrations of peptide and percentage haemolysis estimated by A₄₁₅. Control peptide (insulin) with infected red cells (10% trophozoite-stage parasitaemia, solid line); ΔFd with URBC, (dashed line); ΔFd with 10% parasitaemia (rings 3%, trophozoites 7%, dashed dotted line); and ΔFd with 20% parasitaemia (rings 5%, trophozoites 15%, dotted line). Two other control peptides (prochitinase and E30) behaved like insulin (data not shown). (B) Shows microscopic analysis of the selective sensitivity of trophozoites (Ø, anomalously egressed) vs rings (*, intracellular) at 12 μM ΔFd, (C) shows dose-dependent selective effect of ΔFd on anomalous egress of trophozoites but not rings, monitored microscopically after incubation (3 hr). Data shown were obtained after counting 2,000 erythrocytes.