title: Separation of functionally distinct subpopulations of primitive human hematopoietic cells using rhodamine-123.
abstract: Normal human bone marrow (BM) contains a small population of cells that can give rise to clonogenic progenitors after 5 weeks in long-term culture (LTC). We have previously shown that these LTC-initiating cells (LTC-IC) differ from the majority of directly clonogenic cells with respect to both light-scattering properties and surface antigen expression. In this paper we show that virtually all LTC-IC (94%) are among the 3%-5% of light-density marrow cells that take up relatively low amounts of rhodamine-123 (Rh-123). In contrast, only 70% of erythroid burst-forming units (BFU-E) and 40% of granulocyte-macrophage colony-forming units (CFU-GM) are recovered in the Rh-123-dull fraction. In addition, we have found that double staining of marrow with Rh-123 and phycoerythrin-labeled anti-CD34 antibodies allows the CD34+ cells to be divided into two subpopulations, of which, on average, 35% are Rh-123-dull. Isolation of these CD34+ Rh-123-dull cells thus provides a single-step enrichment of approximately 240-fold in LTC-IC by comparison to the light-density (less than 1.077 g/cm3) fraction of normal BM. This represents an overall enrichment in LTC-IC of approximately 1000-fold. As expected from the results of staining with Rh-123 only, the majority of directly clonogenic cells are present in the CD34+ Rh-123-bright fraction, where they are enriched approximately 40-fold over their concentration in the light-density fraction. These results indicate marked differences in Rh-123 uptake between subsets of primitive human hematopoietic cells currently defined by different functional assays and suggest that RH-123 staining will be useful for the further purification and analysis of these cells.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, University of British Columbia, Vancouver, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Udomsakdi
authors.forename: C J
authors.initials: CJ
authors.lastname: Eaves
authors.forename: H J
authors.initials: HJ
authors.lastname: Sutherland
authors.forename: P M
authors.initials: PM
authors.lastname: Lansdorp
mesh_terms: D018952:Antigens, CD34; D000943:Antigens, Differentiation / Q000276:immunology; D002469:Cell Separation / Q000379:methods*; D002478:Cells, Cultured; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D005434:Flow Cytometry / Q000379:methods; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D006801:Humans; D020112:Rhodamine 123; D012235:Rhodamines / Q000633:toxicity
chemical_list: D018952:Antigens, CD34; D000943:Antigens, Differentiation; D012235:Rhodamines; D020112:Rhodamine 123