Ex Vivo Generation of CD34+ Cells From CD34− Hematopoietic Cells
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 p...
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Veröffentlicht in: | Blood 1999-12, Vol.94 (12), p.4053-4059 |
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Sprache: | eng |
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Zusammenfassung: | 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. |
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ISSN: | 0006-4971 1528-0020 |
DOI: | 10.1182/blood.V94.12.4053 |