Comparative analysis of the immune competencies of the mosquitoes Aedes aegypti and Anopheles gambiae in response to bacterial infections

Mosquitoes combat pathogens by mounting cellular and humoral immune responses. In the current study we assessed the differential ability of Aedes aegypti and Anopheles gambiae to respond to systemic bacterial infections. Survival studies showed that Ae. aegypti are better capable of surviving a bacterial infection than An. gambiae, and that this parallels Ae. aegypti’s increased ability to kill bacteria in their hemocoel. Analysis of the phagocytosis response revealed that both mosquito species are proficient in internalizing and degrading bacteria, but did not explain Ae aegypti’s increased immune competence. Instead, profiling of 19 immunity genes revealed that infection-induced transcriptional induction is significantly elevated in Ae. aegypti when compared to An. gambiae, with the highest differential change seen for the antimicrobial peptides cecropin and defensin. Together, these data show that Ae. aegypti are better equipped to survive a bacterial infection than An. gambiae, and that this increased immune proficiency correlates with Ae. aegypti’s increased induction of antimicrobial peptides and other humoral immune factors.