title: Purification of primitive human hematopoietic cells capable of repopulating immune-deficient mice.
abstract: The purification of primitive human hematopoietic stem cells has been impaired by the absence of repopulation assays. By using a stringent two-step strategy involving depletion of lineage-positive cells followed by fluorescence-activated cell sorting, we have purified a cell population that is highly enriched for cells capable of multilineage repopulation in nonobese diabetic/severe combined immunodeficient (NOD/SCID) recipients. These SCID-repopulating cells (SRCs) were exclusively found in a cell fraction that expressed high levels of CD34 and no CD38. Through limiting dilution analysis using Poisson statistics, we calculated a frequency of 1 SRC in 617 CD34(+) CD38(-) cells. The highly purified SRC were capable of extensive proliferation in NOD/SCID mice. Mice transplanted with 1 SRC (at limiting cell doses) were able to produce approximately 400, 000 progeny 6 weeks after the transplant. Detailed flow cytometric analysis of the marrow of highly engrafted mice demonstrated both lymphoid and myeloid differentiation, as well as the retention of a significant fraction of CD34(+) CD38(-) cells. These highly purified fractions should be useful for identification of the cellular and molecular mechanisms that regulate primitive human hematopoietic cells. Moreover, the ability to detect and purify primitive cells provides a means to develop conditions for maintaining and/or expanding these cells during in vitro culture.
authors.affiliation: Department of Genetics, Research Institute, Hospital for Sick Children and Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Bhatia
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.forename: U
authors.initials: U
authors.lastname: Kapp
authors.forename: D
authors.initials: D
authors.lastname: Bonnet
authors.forename: J E
authors.initials: JE
authors.lastname: Dick
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000818:Animals; D015703:Antigens, CD / Q000032:analysis* / Q000096:biosynthesis; D018952:Antigens, CD34 / Q000032:analysis; D000943:Antigens, Differentiation / Q000032:analysis; D015139:Blotting, Southern; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D001854:Bone Marrow Cells; D002469:Cell Separation; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000145:classification / Q000166:cytology* / Q000276:immunology; D006801:Humans; D008562:Membrane Glycoproteins; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009699:N-Glycosyl Hydrolases / Q000032:analysis; D016511:Severe Combined Immunodeficiency / Q000276:immunology*; D014183:Transplantation, Heterologous
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; D004247:DNA; D009699:N-Glycosyl Hydrolases; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; C498155:Cd38 protein, mouse; D051997:ADP-ribosyl Cyclase 1