Fig. 4.

Anti-FL antibody inhibits parasite invasion in vitro. (A) Anti-FL antibodies have invasion-inhibitory activity in vitro. The ability of the anti-FL antibodies to inhibit the parasite invasion into erythrocytes was tested in a one-cycle growth inhibition assay. Anti-AMA1 and anti-GST antibodies were used as positive and negative controls, respectively. The error bars represent the standard deviations of the means of the three independent experiments. One-way ANOVA was performed (P < 0.001) and followed by Bonferroni's pairwise multiple-comparison tests to compare anti-GST and anti-FL. (B) GAMA plays a role in the SA-independent invasion pathway. The ability of the anti-FL antibody to inhibit parasite invasion into neuraminidase-treated erythrocytes was tested in a one-cycle growth inhibition assay. Anti-GST antibody was used as a negative control. The bars represent the standard deviations of the means of the three independent experiments. (C) Anti-FL antibodies inhibit parasite invasion in a dose-dependent manner in vitro. The graph shows that the anti-FL antibodies, both total and antigen-specific IgGs, inhibited the invasion and/or growth in a dose-dependent manner in a one-cycle growth inhibition assay, as determined by measuring parasite LDH. The ELISA unit value was assigned as the reciprocal of the dilution giving an optical density (OD) at 415 nm equal to 1 in a standardized assay.