title: Molecular cloning and functional characterization of avian interleukin-19.
abstract: The present study describes the cloning and functional characterization of avian interleukin (IL)-19, a cytokine that, in mammals, alters the balance of Th1 and Th2 cells in favor of the Th2 phenotype. The full-length avian IL-19 gene, located on chromosome 26, was amplified from LPS-stimulated chicken monocytes, and cloned into both prokaryotic (pET28a) and eukaryotic (pcDNA3.1) expression vectors. The confirmed avian IL-19 amino acid sequence has 66.5% homology with human and murine IL-19, with a predicted protein sequence of 176 amino acids. Analysis of avian IL-19 amino acid sequence showed six conserved, structurally relevant, cysteine residues as found in mammals, but only one N-glycosylation residue. The recombinant IL-19 (rChIL-19) expressed in the prokaryotic system was purified by Ni(+)-resin column followed by endotoxin removal. Using purified avian rChIL-19, expression of Th2 cytokines was measured in splenocytes using quantitative real-time PCR (qRT-PCR). In the presence of rChIL-19, expression levels of IL-4 and IL-13, as well as IL-10, were significantly increased after 6- and 12 h treatments. This was confirmed by treating splenocytes with supernatants from IL-19 transfected cells. Also, avian monocytes incubated with rChIL-19 displayed increased expression of IL-1beta, IL-6, and IL-19. This study represents the first report for the cloning, expression, and functional characterization of avian IL-19. Taken together, avian IL-19 function seems to be conserved and similar to that of mammals and may play an important role in responses to intracellular poultry pathogens like bacteria and protozoa.
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Tech, VA, United States.
authors.forename: Sungwon
authors.initials: S
authors.lastname: Kim
authors.forename: Kate B
authors.initials: KB
authors.lastname: Miska
authors.forename: Audrey P
authors.initials: AP
authors.lastname: McElroy
authors.forename: Mark C
authors.initials: MC
authors.lastname: Jenkins
authors.forename: Ray H
authors.initials: RH
authors.lastname: Fetterer
authors.forename: Chasity M
authors.initials: CM
authors.lastname: Cox
authors.forename: Lindsay H
authors.initials: LH
authors.lastname: Stuard
authors.forename: Rami A
authors.initials: RA
authors.lastname: Dalloul
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000187:drug effects; D018836:Inflammation Mediators / Q000276:immunology; D007378:Interleukins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D009569:Nitric Oxide / Q000096:biosynthesis; D010802:Phylogeny; D011994:Recombinant Proteins / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D018418:Th2 Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology
chemical_list: D018836:Inflammation Mediators; D007378:Interleukins; D011994:Recombinant Proteins; D009569:Nitric Oxide