title: Long-term erythropoiesis from constant numbers of CD34+ cells in serum-free cultures initiated with highly purified progenitor cells from human bone marrow.
abstract: To directly study the biological properties of purified hematopoietic colony-forming cell precursors, cells with a CD34+ CD45RAlo CD71lo phenotype were purified from human bone marrow using density separation and fluorescence-activated cell sorting, and were cultured in serum-free culture medium supplemented with various cytokines. In the presence of interleukin 3 (IL-3), IL-6, erythropoietin, and mast cell growth factor (a c-kit ligand), cell numbers increased approximately 10(6)-fold over a period of 4 wk, and the percentage of cells that expressed transferrin receptors (CD71) increased from less than 0.1% at day 0 to greater than 99% at day 14. Interestingly, the absolute number of CD34+ CD71lo cells did not change during culture. When CD34+ CD71lo cells were sorted from expanded cultures and recultured, extensive cell production was repeated, again without significant changes in the absolute number of cells with the CD34+ CD71lo phenotype that were used to initiate the (sub)cultures. These results document that primitive hematopoietic cells can generate progeny without an apparent decrease in the size of a precursor cell pool.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
authors.forename: P M
authors.initials: PM
authors.lastname: Lansdorp
authors.forename: W
authors.initials: W
authors.lastname: Dragowska
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000378:metabolism; D018952:Antigens, CD34; D001854:Bone Marrow Cells; D002469:Cell Separation / Q000379:methods; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient / Q000379:methods; D003114:Colony-Forming Units Assay; D016895:Culture Media, Serum-Free; D016207:Cytokines / Q000494:pharmacology*; D004261:DNA Replication / Q000187:drug effects; D004920:Erythropoiesis / Q000187:drug effects / Q000502:physiology*; D004921:Erythropoietin / Q000494:pharmacology; D005434:Flow Cytometry / Q000379:methods; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D010641:Phenotype; D011990:Receptors, Transferrin / Q000187:drug effects / Q000378:metabolism; D019089:Stem Cell Factor; D013936:Thymidine / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D016895:Culture Media, Serum-Free; D016207:Cytokines; D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D015850:Interleukin-6; D011990:Receptors, Transferrin; D019089:Stem Cell Factor; D004921:Erythropoietin; D013936:Thymidine