title: Intrinsic potential of phenotypically defined human hemopoietic stem cells to self-renew in short-term in vitro cultures.
abstract: In search for culture conditions that will facilitate hemopoietic stem cell (HSC) replication while preserving their primitive properties, we have made use of a multi-parameter FACS assay to define HSCs on basis of their phenotypic characteristics, i.e., CD34++CD33,38,71(-). Bone marrow and umbilical cord blood samples of CD34(+) cells from 31 donors were loaded with the membrane dye PKH26 and each exposed to various culture conditions for 6 days. The cells that retained the primitive CD34(++)CD33,38,71(-) phenotype were analysed for the number of cell replications they underwent, by measuring loss of PKH26 fluorescence after 6 days. A most striking observation was the large inter-sample variation in the proliferative response of cells that retained the CD34(++)CD33,38,71(-) phenotype. In general, samples could be characterised as either good- or poorly-replicating, according to the proliferation property of their CD34(++)CD33,38,71(-) subset. In comparison to this 'intrinsic' potential, the effects of the applied growth stimuli on CD34(++)CD33,38,71(-) cell replication were negligible. In contrast, the overall recovery of the CD34(++)CD33,38,71(-) cells was clearly dependent on the culture stimuli. Of the various conditions tested, serum-free cultures with pre-established stroma maintained the cells with this primitive phenotype most effectively. In cultures supplemented with various combinations of recombinant HGFs, HSC differentiation prevailed. These findings with phenotypically defined HSCs should assist in the design of systems for expansion and ex vivo gene therapy of early hemopoietic cells.
authors.affiliation: Department of Molecular Cell Biology, Leiden University Medical Centre, The Netherlands. s.knaan@introgene.com
authors.forename: S
authors.initials: S
authors.lastname: Knaän-Shanzer
authors.forename: S F
authors.initials: SF
authors.lastname: Verlinden
authors.forename: V W
authors.initials: VW
authors.lastname: van Beusechem
authors.forename: D W
authors.initials: DW
authors.lastname: Van Bekkum
authors.forename: D
authors.initials: D
authors.lastname: Valerio
mesh_terms: D000328:Adult; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001773:Blood Cells / Q000166:cytology / Q000187:drug effects; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D003470:Culture Media / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology / Q000502:physiology; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D009928:Organ Specificity; D010641:Phenotype; D017154:Stromal Cells / Q000166:cytology
chemical_list: D015703:Antigens, CD; D003470:Culture Media; D016895:Culture Media, Serum-Free