FIG 2.

Contributions of antibodies to MSP-1 to growth inhibitory activity. (A) Growth inhibitory activity of protein G-purified IgG from 11 semi-immune donors in three independent experiments, each with triplicate measurements. Statistical differences in the GI activities of the semi-immune individuals and a malaria-naive pool were assessed by t tests. *, P ≤ 0.05; ***, P ≤ 0.001. (B) Antigen-reversal GIA with increasing concentrations of MSP-1D. P. falciparum (3D7) parasites were cultured in the presence of purified IgG and increasing concentrations of competitor antigen MSP-1D for one parasite cycle (40 h). The readout is the activity of Plasmodium LDH (pLDH). Mean values are shown with standard deviations; statistical differences were assessed using paired t tests (donor 6, P = 0.024).