title: Cloning, in vitro expression and bioactivity of duck interleukin-18.
abstract: The encoding sequence for duck IL-18 was obtained, using reverse transcription-polymerase chain reaction, from mRNA harvested from Con A-stimulated Gushi (GS) duck splenic mononuclear cells. Recombinant duck IL-18 (rduIL-18) was produced in a prokaryotic expression system. In vitro bioactivity of rduIL-18 was determined in a lymphocyte proliferation assay and in vivo bioactivity of rduIL-18 was assessed by addition to a vaccine. Monoclonal antibody (mAb) and polyclonal antibodies (pAbs) specific for rduIL-18 were generated and subsequently characterized by ELISA, Western blot and neutralizing assays. Sequence analysis of GS duck IL-18 demonstrated an open reading frame (ORF) of 603 base pairs encoding for a 200 amino acid precursor protein. The duck encoding sequence shares 85.3% similarity to the chicken equivalent, at the nucleotide level. A His-duIL-18 fusion protein was recognized in Western blot by mAbs against duck and chicken IL-18 (chIL-18), but not by mAb against human IL-18. Recombinant duIL-18 induced in vitro proliferation of Con A-stimulated duck splenocytes and enhanced the immune response of ducks vaccinated with an inactivated oil emulsion vaccine against avian influenza virus. PAb and mAb 5B2 against rduIL-18 had neutralizing ability, inhibiting the biological activities of both recombinant duIL-18 and endogenous duIL-18. The results indicate that rduIL-18 has the potential to be used as an immunoadjuvant, and the mAb against rduIL-18 further facilitates basic immunobiological studies of the role of IL-18 in the avian immune system.
authors.affiliation: College of Animal Husbandry and Veterinary, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Chen
authors.forename: Bao-An
authors.initials: BA
authors.lastname: Cui
authors.forename: Ping-An
authors.initials: PA
authors.lastname: Xia
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Li
authors.forename: Gong-Zheng
authors.initials: GZ
authors.lastname: Hu
authors.forename: Ming-Fan
authors.initials: MF
authors.lastname: Yang
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Zhang
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Wang
authors.forename: Su-Fang
authors.initials: SF
authors.lastname: Cao
authors.forename: Long-Xian
authors.initials: LX
authors.lastname: Zhang
authors.forename: Xiang-Tao
authors.initials: XT
authors.lastname: Kang
authors.forename: Ke
authors.initials: K
authors.lastname: Tu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology; D001483:Base Sequence; D015153:Blotting, Western / Q000662:veterinary; D002645:Chickens; D003001:Cloning, Molecular; D004372:Ducks / Q000235:genetics* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004926:Escherichia coli / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology / Q000494:pharmacology; D020382:Interleukin-18 / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010802:Phylogeny; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment
chemical_list: D000911:Antibodies, Monoclonal; D007252:Influenza Vaccines; D020382:Interleukin-18; D011994:Recombinant Proteins