title: Cloning and characterization of rainbow trout interleukin-17A/F2 (IL-17A/F2) and IL-17 receptor A: expression during infection and bioactivity of recombinant IL-17A/F2.
abstract: Lower vertebrates have been found to possess genes that have similar homology to both interleukin (IL)-17A and IL-17F, which have been termed IL-17A/F. In fish species, several of these genes can be present, but, to date, very little is known about their functional activity. This article describes the discovery and sequence analysis of a rainbow trout (Oncorhynchus mykiss) IL-17A/F2 molecule and an IL-17RA receptor. In addition, the bioactivity of the trout IL-17A/F2 is investigated for the first time in any species. The predicted IL-17A/F2 and IL-17RA proteins consist of 146 and 966 amino acids (aa), respectively, with both molecules containing conserved family motifs. Expression analysis revealed high constitutive expression of trout IL-17A/F2 in mucosal tissues from healthy fish, suggesting a potential role in mucosal immunity. When the modulation of IL-17A/F2 and IL-17RA in vitro was analyzed, it was observed that the two molecules were similarly affected. The expression of IL-17A/F2 was also induced in head kidney during bacterial, parasitic, and viral infections, revealing a possible function in defense against such pathogens. However, downregulation of IL-17RA was seen in some tissues and infections. The recombinant IL-17A/F2 protein was produced in Escherichia coli and was found to affect the expression of an antimicrobial peptide and the proinflammatory cytokines IL-6 and IL-8 in splenocytes. Consistent with mammalian IL-17 homologues, our expression and bioactivity results imply that trout IL-17A/F2 plays an important role in promoting inflammatory and host innate immune responses directed against different pathogen groups.
authors.affiliation: Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, Scotland, United Kingdom. m.monte@abdn.ac.uk
authors.forename: Milena M
authors.initials: MM
authors.lastname: Monte
authors.forename: Tiehui
authors.initials: T
authors.lastname: Wang
authors.forename: Jason W
authors.initials: JW
authors.lastname: Holland
authors.forename: Jun
authors.initials: J
authors.lastname: Zou
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology; D020381:Interleukin-17 / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D053722:Receptors, Interleukin-17 / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D020381:Interleukin-17; D015850:Interleukin-6; D016209:Interleukin-8; D053722:Receptors, Interleukin-17; D011994:Recombinant Proteins