title: Analysis of interleukin 6 receptor and gp130 expressions and proliferative capability of human CD34+ cells.
abstract: We recently demonstrated that stimulation of gp130 by a combination of soluble interleukin 6 receptor (sIL-6R) and IL-6 but not IL-6 alone significantly stimulates the ex vivo expansion of primitive hematopoietic progenitors and the generation of erythroid cells from human CD34+ cells in the presence of stem cell factor (SCF). Here, we show that gp130 is found low positively on most CD34+ cells, whereas IL-6R is expressed on only 30-50% of these cells. Although most of the colonies generated from FACS-sorted CD34+IL-6R+ cells were granulocyte/macrophage (GM) colonies, CD34+IL-6R- cells gave rise to various types of colonies, including erythroid bursts, GM, megakaryocytes, and mixed colonies in methylcellulose culture with a combination of IL-6, sIL-6R, and SCF. Similar results were obtained in culture supplemented with a combination of IL-3, IL-6, SCF, granulocyte colony-stimulating factor, erythropoietin, and thrombopoietin. A limiting dilution analysis of long-term culture-initiating cells (LTC-IC) showed that the CD34+IL-6R- cells contained a larger number of LTC-IC than did the CD34+IL-6R+ cells. In a serum-free suspension of CD34+IL-6R- cells, the addition of sIL-6R to the combination of IL-6 and SCF dramatically increased the total and multipotential progenitors, whereas CD34+IL-6R+ cells failed to do so under the same conditions. These results indicate that most of the erythroid, megakaryocytic, and primitive human hematopoietic progenitors are included in the IL-6R- populations, and the activation of gp130 on these progenitors can be achieved by a complex of IL-6-sIL-6R, but not by IL-6 alone. The present culture system using IL-6, sIL-6R, and SCF may provide a novel approach for ex vivo expansion of human primitive hematopoietic progenitors.
authors.affiliation: Department of Clinical Oncology, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tajima
authors.forename: K
authors.initials: K
authors.lastname: Tsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Ebihara
authors.forename: X
authors.initials: X
authors.lastname: Sui
authors.forename: R
authors.initials: R
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Muraoka
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: K
authors.initials: K
authors.lastname: Yamada
authors.forename: K
authors.initials: K
authors.lastname: Yasukawa
authors.forename: T
authors.initials: T
authors.lastname: Taga
authors.forename: T
authors.initials: T
authors.lastname: Kishimoto
authors.forename: T
authors.initials: T
authors.lastname: Nakahata
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis*; D018952:Antigens, CD34 / Q000032:analysis*; D001854:Bone Marrow Cells; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division; D050822:Cytokine Receptor gp130; D015672:Erythroid Precursor Cells; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D006098:Granulocytes; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D015850:Interleukin-6 / Q000494:pharmacology; D008264:Macrophages; D008562:Membrane Glycoproteins / Q000032:analysis*; D018123:Receptors, Interleukin / Q000032:analysis*; D019947:Receptors, Interleukin-6; D019089:Stem Cell Factor / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; C494199:IL6ST protein, human; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D018123:Receptors, Interleukin; D019947:Receptors, Interleukin-6; D019089:Stem Cell Factor; D050822:Cytokine Receptor gp130