Aedes aegypti Hemocytes Mediate Antiviral Immunity.

Hemocytes play several key roles in the mosquito's immune response. Despite most of our understanding regarding their immunological role concerns their responses against bacteria, fungi, and Plasmodium, our knowledge of hemocyte's role in antiviral defense is poorly understood. We performed a comprehensive comparative transcriptomic analysis between the dengue vector Aedes aegypti's two major immune cell types, hemocytes and fat body, revealing a plethora of differentially expressed immune genes that indicates a high level of functional specialization as well as complementation between the two immune cell types. Our transcriptomic approach yielded molecular insights into the antiviral immune response of Ae. aegypti hemocytes during systemic infection. In fact, hemocytes showed abundant expression of RNAi pathway genes under naive conditions and upregulated many of these upon dengue virus (DENV) infection. Furthermore, chemical depletion of phagocytic hemocytes resulted in a higher DENV systemic infection. Our results suggest that hemocytes possess mechanisms to control systemic viral infections.