Immune response of Drosophila melanogaster to infection with the flagellate parasite Crithidia spp

• Published in: Insect biochemistry and molecular biology Vol. 31; no. 2; pp. 129 - 137
• Main Authors: Boulanger, Nathalie, Ehret-Sabatier, Laurence, Brun, Reto, Zachary, Daniel, Bulet, Philippe, Imler, Jean-Luc
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2001; Elsevier
• Subjects: Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides - genetics; Antimicrobial peptides; Crithidia; Crithidia - immunology; Crithidia - pathogenicity; Defensins - genetics; Drosophila melanogaster; Drosophila melanogaster - immunology; Drosophila melanogaster - parasitology; Drosophila Proteins; Flagellate parasite; Gene Expression; Glycopeptides - biosynthesis; Glycopeptides - genetics; Hemocytes - immunology; Hemocytes - parasitology; Insect immunity; Insect Proteins - biosynthesis; Insect Proteins - genetics; Life Sciences; Phagocytosis - immunology; Insect immunity; Crithidia; Flagellate parasite; Drosophila melanogaster; Antimicrobial peptides
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/S0965-1748(00)00096-5

Insects are able to recognize invading microorganisms and to mount an immune response to bacterial and fungal infections. Recently, the fruitfly Drosophila melanogaster has emerged as a promising invertebrate model to investigate innate immunity because of its well-characterized genetics. Insects are also vectors of numerous parasites which can trigger an immune response. We have investigated the interaction of Drosophila melanogaster with the flagellate protozoan Crithidia spp. We show that a per os parasitic infection triggers the synthesis of several antimicrobial peptides. By reverse phase HPLC and mass spectrometry, peptides were shown to be present in the hemolymph and not in the gut tissue, suggesting the presence of immune messengers between the site of the infection, namely the gut, and the fat body, the main site of synthesis for antimicrobial peptides. Interestingly, we have identified one molecule which is specifically induced in the hemolymph after infection with Crithidia, but not with bacteria, suggesting that Drosophila can discriminate between pathogens. When flagellates were injected into the hemolymph, a low synthesis of antimicrobial peptides was observed together with phagocytosis of parasites by circulating hemocytes. The data presented here suggest that Drosophila– Crithidia spp. represents an interesting model to study host defense against protozoan parasites.