FIG 4.

Additional feeding enables the recognition and killing of P. berghei oocysts by mosquito complement. Immunofluorescence assays were performed to examine TEP1 localization on developing oocysts when maintained on sugar or following an additional blood meal. P. berghei oocysts were identified by circumsporozoite protein (CSP) staining and residual signal from the mCherry-parasite background, enabling determination of the percentage of TEP1⁺ oocysts from both experimental conditions (A). Similar experiments were performed following P. falciparum infection (B). Additional feeding experiments were performed on either wild-type (WT) or mutant TEP1 (ΔTEP1) lines to confirm the involvement of mosquito complement in P. berghei oocyst recognition and killing (C). Oocyst numbers were evaluated 8 days postinfection. (D) Model for the role of mosquito complement via TEP1 recognition and killing of P. berghei oocysts. The percentage of TEP1⁺ oocysts for P. berghei and P. falciparum studies are displayed as the mean (+ standard error of the mean [SEM]) and analyzed by Mann-Whitney U test for direct comparison (**, P < 0.01; ****, P < 0.0001). Bar, 10 μm. n, number of mosquitoes examined; ns, not significant. For each figure, the feeding status is designated by a dark red circle demonstrating an initial P. berghei or P. falciparum parasite infection. Additional blood (pink circle) or protein (blue circle) meals at either 4 days postinfection are designated by their respective colors.