Supplementary Material for: Anopheles gambiae Blood Feeding Initiates an Anticipatory Defense Response to Plasmodium berghei

Mosquitoes have potent innate defense mechanisms that protect them
from infection by diverse pathogens. Much remains unknown about how
different pathogens are sensed and specific responses triggered.
Leucine-Rich repeat IMmune proteins (LRIMs) are a mosquito-specific
family of putative innate receptors. Although some LRIMs have been
implicated in mosquito immune responses, the function of most family
members is largely unknown. We screened Anopheles gambiae LRIMs by RNAi for effects on mosquito infection by rodent malaria and found that LRIM9 is a Plasmodium berghei antagonist
with phenotypes distinct from family members LRIM1 and APL1C, which are
key components of the mosquito complement-like pathway. LRIM9
transcript and protein levels are significantly increased after blood
feeding but are unaffected by Plasmodium or midgut microbiota.
Interestingly, LRIM9 in the hemolymph is strongly upregulated by direct
injection of the ecdysteroid, 20-hydroxyecdysone. Our data suggest that
LRIM9 may define a novel anti-Plasmodium immune defense mechanism
triggered by blood feeding and that hormonal changes may alert the
mosquito to bolster its defenses in anticipation of exposure to
blood-borne pathogens.