FIG. 3.

Analysis of P. falciparum IRBC binding to the placental CSPG at different parasite generations. 3D7-CSA and FCR3-CSA IRBCs with 20 to 25% parasitemia were assayed. Binding assay was performed for IRBCs at 2, 4, 8, 12, 16, 20, 24, 28, and 32 cell cycles after selecting for CSPG binding. At each cell cycle, expressed values are percent IRBCs bound per mm² and are means from three independent experiments done in duplicate; vertical bars indicate standard errors. The binding capacities of both 3D7-CSA and FCR3-CSA IRBCs were more or less similar up to eight generations and then decreased gradually. At the 32nd generation the binding capacity of IRBCs was ∼31% of that at the 2nd generation following selection for CSPG binding.