title: Ex vivo generation of CD34(+) cells from CD34(-) hematopoietic cells.
abstract: The human Lin(-)CD34(-) cell population contains a newly defined class of hematopoietic stem cells that reconstitute hematopoiesis in xenogeneic transplantation systems. We therefore developed a culture condition in which these cells were maintained and then acquired CD34 expression and the ability to produce colony-forming cells (CFC) and SCID-repopulating cells (SRCs). A murine bone marrow stromal cell line, HESS-5, supports the survival and proliferation of Lin(-)CD34(-) cells in the presence of fetal calf serum and human cytokines thrombopoietin, Flk-2/Flt-3 ligand, stem cell factor, granulocyte colony-stimulating factor, interleukin-3, and interleukin-6. Although Lin(-)CD34(-) cells do not initially form any hematopoietic colonies in methylcellulose, they do acquire the colony-forming ability during 7 days of culture, which coincides with their conversion to a CD34(+) phenotype. From 2.2% to 12.1% of the cells became positive for CD34 after culture. The long-term multilineage repopulating ability of these cultured cells was also confirmed by transplantation into irradiated NOD/SCID mice. These results represent the first in vitro demonstration of the precursor of CD34(+) cells in the human CD34(-) cell population. Furthermore, the in vitro system we reported here is expected to open the way to the precise characterization and ex vivo manipulation of Lin(-)CD34(-) hematopoietic stem cells.
authors.affiliation: Research Center for Cell Transplantation, Department of Pediatrics, and the Department of Hematology, Tokai University, School of Medicine, Kanagawa, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Ando
authors.forename: J
authors.initials: J
authors.lastname: Chargui
authors.forename: H
authors.initials: H
authors.lastname: Kawada
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Tsuji
authors.forename: T
authors.initials: T
authors.lastname: Hotta
authors.forename: S
authors.initials: S
authors.lastname: Kato
mesh_terms: D000818:Animals; D018952:Antigens, CD34; D002450:Cell Communication; D002454:Cell Differentiation; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D051379:Mice; D017154:Stromal Cells / Q000166:cytology
chemical_list: D018952:Antigens, CD34