title: Preparation of a recombinant chimaera of insulin-like growth factor II and interleukin 3 with high proliferative potency for haemopoietic cells.
abstract: We have found that a slightly modified insulin-like growth factor II (IGF II) consisting of a chimaera of bombyxin and human IGF II (BOMIGF) is properly secreted in insect cells by using the baculovirus expression system. Human interleukin 3 (IL-3) was attached to the C-terminal amino acid residue of BOMIGF with peptide linkers containing five or twelve residues. Only the chimaera with the 12-residue linker had biological activities of both IGF II and IL-3. The chimaera had a significantly higher mitogenic activity than IL-3 in cell cultures of the human haemopoietic cell line TF-1 and its effect could be observed even at femtomolar concentrations. It was also able to stimulate thymidine incorporation in IGF II-dependent bovine fetal erythroid cells. The chimaera significantly increased the number of macroscopic haemopoietic colonies in cultures of human peripheral blood in comparison with IL-3 or mixtures of IL-3 and BOMIGF in vitro. Subcutaneous injection of a BOMIGF-mouse IL-3 chimaera in normal C57BL/6 mice resulted in a significant increase of the number of spleen stem cells producing macroscopic haemopoietic colonies. This new system for the biosynthesis of IGF-cytokine fusion proteins in insect cells might prove advantageous for the low-cost and high-yield production of molecules with complementary or synergistic biological activities.
authors.affiliation: Endocrine Laboratory, Royal Victoria Hospital, Montreal, Canada.
authors.forename: M R
authors.initials: MR
authors.lastname: Difalco
authors.forename: L F
authors.initials: LF
authors.lastname: Congote
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000235:genetics; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D005822:Genetic Vectors / Q000138:chemical synthesis / Q000494:pharmacology; D016298:Hematopoietic Cell Growth Factors / Q000138:chemical synthesis* / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics* / Q000494:pharmacology; D007377:Interleukin-3 / Q000235:genetics* / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000138:chemical synthesis* / Q000235:genetics / Q000494:pharmacology
chemical_list: D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D009479:Neuropeptides; D011993:Recombinant Fusion Proteins; C075028:bombyxins; D007335:Insulin-Like Growth Factor II