Fig. 2: Monitoring of P. falciparum specific antibody responses in participants during mild malaria illness.

A Number of Pf antigens recognized by participant’s plasma IgG (top) and abundance (bottom) of P. falciparum-reactive plasma IgG antibodies (mean intensity) in plasma determined on Pf antigen array. The center line of box plots denotes medians of data points and the box hinges correspond to the 1st and 3rd quartiles, the whiskers of the box and whisker plot extend from the box to the minimum and maximum observations within 1.5 times the IQR of the lower and upper quartile, respectively. Two-sided Welch’s unpaired t-test was conducted between indicated groups (susceptible, <13 yr (n = 36, pink), protected, <13 yr (n = 11, orange) and protected, ≥13 yr (n = 17, green) *p < 0.05, **p < 0.01, ***p < 0.001. B Heatmap of normalized levels of IgG antibodies in individual participants (columns) against 45 Pf antigens (rows) that are significantly higher in protected versus susceptible groups (Two-sided Mann–Whitney test, p < 0.0001). C Pf merozoite opsonization assay with YOYO-1 labeled Pf merozoites incubated with indicated participant’s plasma, washed and then co-cultured with THP-1 cells. FACS plots of a representative sample within indicated groups, quantifying YOYO1⁺ THP1 cells after the co-culture (left). Summary of %YOYO1⁺ THP1 cells (right) indicating % Pf merozoite uptake when labeled merozoites were incubated with or without indicated plasma (n = 3) from susceptible (n = 8, pink), protected < 13yr (n = 6, orange), protected ≥13 yr (n = 7, green) and co-cultured with THP1 cells. Two-sided Welch’s unpaired t test were conducted between indicated groups, *p < 0.05, **p < 0.01, ***p < 0.001. Pool of two independent experiments represented as individual data and means ± SEM (C).