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Molecular immune responses of the mosquito Anopheles gambiae to bacteria and malaria parasites

Dimopoulos, G., Richman, A., Muller, H.M., Kafatos, F.C.
Proceedings of the National Academy of Sciences of the United States of America 1997 v.94 no.21 pp. 11508-11513
Anopheles gambiae, complementary DNA, animal proteins, binding proteins, serine proteinases, nucleotide sequences, amino acid sequences, gene expression, messenger RNA, midgut, Micrococcus luteus, Escherichia coli, Plasmodium berghei, immune response, larvae, adults, beta-glucanase
Immune responses of the malaria vector mosquito Anopheles gambiae were monitored systematically by the induced expression of five RNA markers after infection challenge. One newly isolated marker encodes a homologue of the moth Gram-negative bacteria-binding protein (GNBP), and another corresponds to a serine protease-like molecule. Additional previously described markers that respond to immune challenge encode the antimicrobial peptide defensin, a putative galactose lectin, and a putative serine protease. Specificity of the immune responses was indicated by differing temporal patterns of induction of specific markers in bacteria-challenged larvae and adults, and by variations in the effectiveness of different microorganisms and their components for marker induction 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 the anterior and the other in the posterior midgut. Marker induction indicates a significant role of the midgut in insect innate immunity. Immune responses to the penetration of the midgut epithelium by a malaria parasite occur both within the midgut itself and elsewhere in the body, suggesting an immune-related signaling process.