Fig. 4: Anti-CSP IgG levels increase after repetitive CHMI.

Plasma levels of IgM and IgG antibodies against CSP repeat (NANP₈) and the GLURP R2 repeat peptides were determined by ELISA for all participants (CHMI1 n = 8, CHMI2 n = 8, CHMI3 n = 8, CHMI4 n = 5) on D1 before exposure to Pf-infected mosquitoes, D6, D8, on day of treatment (DRx) and 7 days after treatment (DRx + 7) for each CHMI. For all participants the mean optical density (OD) at 410 nm at a 1/300 dilution subtracted by the OD 410 nm of a 1/300 dilution of the participants’ baseline samples (matched mock samples) is plotted. Participants with delayed patency at their last CHMI are shown in green. The population mean and standard error of the mean (SEM) at each time is indicated. Statistical differences were determined through CHMI 1-3 relative to D1 of CHMI 1, using Dunn’s multiple comparisons test while due to the smaller samples size a Holm-Šídák’s multiple comparisons test was used for CHMI 4. All P values are two-sided and the source data are provided as a Source Data file.