FIG 5.

Biofunctional assays on rMSP3N to evaluate vaccine efficacy. (A) Bar graph showing percentage of opsonic phagocytosis of merozoites by THP-1 cells mediated by either test or control antibodies at a 0.035-mg/ml concentration. Human MSP3N-specific purified antibodies promoted strong opsonic phagocytosis activity, which was similar to that of the positive control (HIG). Opsonic phagocytosis activity is expressed as the average of triplicate measurements with standard errors of the means. HIG, hyperimmune immunoglobulin G; NIG, malaria-naive immunoglobulin G; UOP, unopsonized merozoites; MSP, merozoite surface protein; hAb, human antibody. (B) Line graph showing invasion inhibition assay on schizont-stage parasites using rabbit anti-rMSP3N total purified IgG at increasing concentrations; rabbit preimmune total IgG served as a negative control. (C) Line graph representing invasion inhibition using anti-MSP3N human IgGs and merozoite-PfRhopH3N human antibodies in a concentration-dependent manner. FACS analysis was done to determine parasitemia after 40 h of incubation. Bars indicate SEM of duplicate measurements.