title: A synergistic increase in transplantable peripheral blood stem cells in mice by co-administration of recombinant human interleukin 6 and recombinant human granulocyte colony-stimulating factor.
abstract: We examined the effects of co-administration of recombinant human (rh) IL-6 (10 micrograms/day) and rh granulocyte colony-stimulating factor (G-CSF) (0.35 micrograms/day) on the number of peripheral blood cells and peripheral progenitor cells in mice. Among blood cells counts, only white blood cells were synergistically enhanced by co-administration of rhIL-6 and rhG-CSF. Moreover, it was found that co-administration of rhIL-6 and rhG-CSF also caused a marked synergistic increase in the number of peripheral blood progenitor cells. Namely, in combination with rhG-CSF, which alone induced a 170-fold increase in peripheral granulocyte-macrophage colony-forming units (CFU-GM) on day 14, rhIL-6 synergistically increased the number of CFU-GM to more than 1600-fold higher than the number in control mice. Administration of rhIL-6 alone induced a 46-fold increase in CFU-GM. Similar synergistic increases of other hematopoietic progenitors, such as colony-forming units in spleen and megakaryocyte colony-forming units in blood, were also observed in mice co-administered rhIL-6 and rhG-CSF. The survival rate of lethally irradiated recipient mice transplanted with mononuclear cells from 100 microliters of blood from mice administered rhIL-6 and/or rhG-CSF was examined. When mononuclear cells from mice co-administered rhIL-6 and rhG-CSF were injected, survival rate at day 100 was 92%. In contrast, recipient mice transplanted with mononuclear cells from mice administered either rhIL-6 or rhG-CSF alone showed a survival rate of 31% or 46%, respectively, although transplantation of mononuclear cells from control mice failed to rescue any lethally irradiated recipient mice. These results suggest that co-administration of rhIL-6 and rhG-CSF may be useful for peripheral blood stem cell transplantation.
authors.affiliation: Central Research Laboratories, Ajinomoto Co, Inc., Yokohama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: A
authors.initials: A
authors.lastname: Okano
authors.forename: C
authors.initials: C
authors.lastname: Suzuki
authors.forename: A
authors.initials: A
authors.lastname: Konishi
authors.forename: Y
authors.initials: Y
authors.lastname: Akiyama
authors.forename: T
authors.initials: T
authors.lastname: Ishibashi
authors.forename: K
authors.initials: K
authors.lastname: Ozawa
authors.forename: S
authors.initials: S
authors.lastname: Asano
mesh_terms: D000818:Animals; D004357:Drug Synergism; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D015850:Interleukin-6; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor