title: Bioactive murine and human interleukin-12 fusion proteins which retain antitumor activity in vivo.
abstract: Interleukin-12 (IL-12) is unique amongst cytokines in being a disulfide-linked heterodimer of two separately encoded subunits (p35 and p40). We expressed single chain IL-12 proteins from retroviral constructs in which the two IL-12 subunits were linked by a 6-15 amino acid polypeptide linker, with deletion of the 22 amino acid leader sequence of the trailing subunit. The murine fusion protein IL-12.p40.L.delta p35 containing a (Gly4Ser)3 linker was stably expressed, bioactive in vitro, and had an apparent specific activity comparable to that of native and recombinant IL-12. Western blotting confirmed that murine IL-12.p40.L.delta p35 retained the linking polypeptide sequences. The analogous human IL-12.p40.L.delta p35 fusion protein containing a Gly6Ser linker was bioactive with an apparent specific activity comparable to recombinant human IL-12. In a preexisting CMS-5 tumor model, CMS-5 cells secreting either native or fusion protein forms of IL-12 prolonged survival and led to complete tumor regression.
authors.affiliation: Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lieschke
authors.forename: P K
authors.initials: PK
authors.lastname: Rao
authors.forename: M K
authors.initials: MK
authors.lastname: Gately
authors.forename: R C
authors.initials: RC
authors.lastname: Mulligan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology*; D012190:Retroviridae / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D011993:Recombinant Fusion Proteins; D018664:Interleukin-12