MOLECULAR IMMUNE-RESPONSES OF THE MOSQUITO ANOPHELES-GAMBIAE TO BACTERIA AND MALARIA PARASITES

Immune responses of the malaria vector mosquito Anopheles gambiae were monitored systematically by the induced expression of five RNA marker s after infection challenge, One newly isolated marker encodes a homol ogue of the moth Gram-negative bacteria-binding protein (GNBP), and an other corresponds to a serine protease-like molecule, Additional previ ously described markers that respond to immune challenge encode the an timicrobial peptide defensin, a putative galactose lectin, and a putat ive serine protease, Specificity of the immune responses was indicated by differing temporal patterns of induction of specific markers in ba cteria-challenged larvae and adults, and by variations in the effectiv eness of different microorganisms and their components for marker indu ction in an immune-responsive cell line, The markers exhibit spatially distinct patterns of expression in the adult female mosquito, Two of them are highly expressed in different regions of the midgut, one in t he anterior and the other in the posterior midgut. Marker induction in dicates a significant role of the midgut in insect innate immunity. Im mune responses to the penetration of the midgut epithelium by a malari a parasite occur both within the midgut itself and elsewhere in the bo dy, suggesting an immune-related signaling process.