title: Epithelial innate immunity. A novel antimicrobial peptide with antiparasitic activity in the blood-sucking insect Stomoxys calcitrans.
abstract: The gut epithelium is an essential interface in insects that transmit parasites. We investigated the role that local innate immunity might have on vector competence, taking Stomoxys calcitrans as a model. S. calcitrans is sympatric with tsetse flies, feeds on many of the same vertebrate hosts, and is thus regularly exposed to the trypanosomes that cause African sleeping sickness and nagana. Despite this, S. calcitrans is not a cyclical vector of these trypanosomes. Trypanosomes develop exclusively in the lumen of digestive organs, and so epithelial immune mechanisms, and in particular antimicrobial peptides (AMPs), may be the prime determinants of the fate of an infection. To investigate why S. calcitrans is not a cyclical vector of trypanosomes, we have looked in its midgut for AMPs with trypanolytic activity. We have identified a new AMP of 42 amino acids, which we named stomoxyn, constitutively expressed and secreted exclusively in the anterior midgut of S. calcitrans. It displays an amphipathic helical structure and exhibits a broad activity spectrum affecting the growth of microorganisms. Interestingly, this AMP exhibits trypanolytic activity to Trypanosoma brucei rhodesiense. We argue that stomoxyn may help to explain why S. calcitrans is not a vector of trypanosomes causing African sleeping sickness and nagana.
authors.affiliation: Institut de Biologie Moléculaire et Cellulaire, 15 Rue René Descartes, 67084 Strasbourg Cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boulanger
authors.forename: Rebecca J L
authors.initials: RJ
authors.lastname: Munks
authors.forename: Joanne V
authors.initials: JV
authors.lastname: Hamilton
authors.forename: Françoise
authors.initials: F
authors.lastname: Vovelle
authors.forename: Reto
authors.initials: R
authors.lastname: Brun
authors.forename: Mike J
authors.initials: MJ
authors.lastname: Lehane
authors.forename: Philippe
authors.initials: P
authors.lastname: Bulet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D018076:DNA, Complementary / Q000378:metabolism; D004175:Diptera; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000276:immunology*; D005260:Female; D005658:Fungi / Q000187:drug effects; D015723:Gene Library; D007413:Intestinal Mucosa / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014346:Trypanosoma brucei brucei / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger