Characterization of Cd34+ Hematopoietic Stem Cells from Human Peripheral Blood By Magnetic Cell Sorting |
CD34+ cells,present at a frequency of 0.18 ± 0.052% among leukocytes from peripheral blood(PB), can be rapidly and efficiently en- riched to a frequency of 38.6-87.1%(&4*4 by high-gradient magnetic cell separation (MACS) for Immunopheno- typing,characterization in colony-forming cell assays, and further purification tohomogeneity (>98%) by multiparameter fluorescence-activated cell sorting(FACS). Enriching PB-CD34+ cells for immunophenotyping allows the detection ofsmall subpopulations, expressing the B-cell antigens CD10, CD19, and CD20, theT-cell antigens CD45RA and CD7, and a small subpopulation expressing highlevels of CD34 which mostly coexpress CD19 CD20 ; and CD38. All PB-CD34 + cells express elevatedlevels of CD71 (transfer-rin receptor), with a subpopulation of high expressingcells, and CD38. Some cells express CD33. MACS-enriched PB-CD34+cells show "normal" hematopoie-tic colony formation in vitro. Theease and efficiency of purification of large numbers of CD34+ cellsfrom PB by MACS is not only relevant for the characterization of migratingstem cells but also opens new possibilities for stem cell transplantation &genetic manipulation of the hematopoietic system.