Figure 4.

Anti-Plasmodium effects of PGE2 priming are mediated by mosquito prophenoloxidases (PPOs). Significant reduction of PPO1 gene expression enhanced oocyst survival at 7 days post-infection (A) PPO1 gene expression was efficiently reduced following RNAi, resulting in a significant increase in P. berghei oocyst survival when evaluated 8 days post-infection. To verify the role of mosquito PPOs in mediating PGE2 immune activation, PPO1 and PPO3 were co-silenced and then primed with either PBS (control) or PGE2 (B). Following challenge with P. berghei, oocyst survival was examined 7 days post-infection. Data were analyzed by an unpaired t test to determine RNAi efficiency and a Mann–Whitney test to assess oocyst survival using GraphPad Prism 7.0. Bars represent mean ± SE of three independent biological replicates. Median oocyst numbers from three or more independent biological replicates are indicated by the horizontal red line. The prevalence of infection (% infected/total) is depicted for mosquitoes under each experimental condition and examined by X² analysis to determine significance. Asterisks denote significance (*P < 0.05, **P < 0.01); ns, not significant. n = number of individual mosquitoes examined.