Fig. 3.

Antibodies among children and adults from PNG to surface antigens expressed by P. falciparum-IEs. IgG binding to the surface of erythrocytes infected with 3D7 SBP1KO (a), E8B SBP1KO (c) and was markedly reduced compared to 3D7 parental and E8B parental parasites, respectively. Assays were performed twice independently; bars represent median and interquartile ranges of samples tested in duplicate (n = 87 for 3D7, n = 91 for E8B); p value was calculated using a paired Wilcoxon signed rank test; IgG binding levels are expressed as geometric mean fluorescence intensity (MFI) for all graphs. A representative selection of serum samples from PNG tested for antibodies to 3D7 SBP1KO (b) and E8B SBP1KO (d). Samples were from malaria-exposed children and adults (P3-P25) (b and d) and non-exposed Melbourne residents (Control). IgG binding to 3D7 SBP1KO and E8B SBP1KO was substantially reduced in most individuals, with adults having a higher proportion of antibody response. There was minimal background reactivity observed among sera from Melbourne residents. Assays were performed twice independently; bars represent mean and range of samples tested in duplicate