title: Construction of an expression system for bioactive IL-18 and generation of recombinant canine distemper virus expressing IL-18.
abstract: Interleukin 18 (IL-18) plays an important role in the T-helper-cell type 1 immune response against intracellular parasites, bacteria and viral infections. It has been widely used as an adjuvant for vaccines and as an anticancer agent. However, IL-18 protein lacks a typical signal sequence and requires cleavage into its mature active form by caspase 1. In this study, we constructed mammalian expression vectors carrying cDNA encoding mature canine IL-18 (cIL-18) or mouse IL-18 (mIL-18) fused to the human IL-2 (hIL-2) signal sequence. The expressed proIL-18 proteins were processed to their mature forms in the cells. The supernatants of cells transfected with these plasmids induced high interferon-γ production in canine peripheral blood mononuclear cells or mouse splenocytes, respectively, indicating the secretion of bioactive IL-18. Using reverse genetics, we also generated a recombinant canine distemper virus that expresses cIL-18 or mIL-18 fused to the hIL-2 signal sequence. As expected, both recombinant viruses produced mature IL-18 in the infected cells, which secreted bioactive IL-18. These results indicate that the signal sequence from hIL-2 is suitable for the secretion of mature IL-18. These recombinant viruses can also potentially be used as immunoadjuvants and agents for anticancer therapies in vivo.
authors.affiliation: Laboratory Animal Research Center, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Yuxiu
authors.initials: Y
authors.lastname: Liu
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sato
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hamana
authors.forename: Navita Anisia
authors.initials: NA
authors.lastname: Moonan
authors.forename: Misako
authors.initials: M
authors.lastname: Yoneda
authors.forename: Xianzhu
authors.initials: X
authors.lastname: Xia
authors.forename: Chieko
authors.initials: C
authors.lastname: Kai
mesh_terms: D000818:Animals; D001681:Biological Assay; D004216:Distemper / Q000276:immunology* / Q000517:prevention & control; D004217:Distemper Virus, Canine / Q000235:genetics / Q000276:immunology*; D004285:Dogs; D005822:Genetic Vectors / Q000235:genetics / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D020382:Interleukin-18 / Q000235:genetics / Q000276:immunology*; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology; D007963:Leukocytes, Mononuclear; D051379:Mice; D010957:Plasmids / Q000235:genetics / Q000276:immunology; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
chemical_list: D020382:Interleukin-18; D007376:Interleukin-2; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D012313:RNA