Proliferation of individual hematopoietic progenitors purified from umbilical cord blood.
In previous studies, we described long-term cultures of subpopulations of CD34+ cord blood cells that were fractionated using antibodies specific for CD45RA and CD71. In the present study, we plated the most primitive CD34+CD45RAlowCD71low cells individually and analyzed the proliferation and expansion kinetics of the various hematopoietic progenitors included in this subpopulation. The proliferation capacity of single progenitors was assessed by the total number of cells produced, and their expansion capacity was assessed by the production of CD34+ and colony-forming cells. Monolineage progenitors (erythroid, granulocyte, and macrophage progenitors) showed the lowest expansion capacity, which correlated with a relatively short life span (< 37 days) of the generated colonies. Among these cells, erythroid progenitors showed the highest proliferative potential. Based on their relative cell content and proliferation/expansion capacities, two types of both granulomacrophagic (GM) and multipotent (Mix) progenitors were identified. GM progenitors producing colonies with > 70% granulocytes had a low expansion capacity and gave rise to colonies that were sustained for < 42 days. A second type of GM progenitors, giving rise to colonies with > 90% macrophages, had a higher expansion capacity and the colonies they produced were sustained for > 72 days. On the other hand, Mix progenitors producing colonies with > 70% erythroid cells had a lower expansion capacity and life span (< 46 days in culture), than Mix progenitors producing colonies with > 90% myeloid cells (life span of > 72 days). These results demonstrate, at the single-cell level, a correlation between the type of progenitor cell and its expansion capacity. In turn, the expansion capacity of the progenitors was correlated with the life span of the colonies produced. Furthermore, our results suggest that in cord blood, at least two types of bipotential myeloid (GM) progenitors and two types of multipotent (Mix) progenitors can be distinguished, that have respectively low and high proliferative and expansion capacity.
Mayani
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Terry Fox Laboratory, B.C. Cancer Research Centre, Vancouver, Canada.
Lansdorp
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PM
D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D002455:Cell Division; D002469:Cell Separation; D002478:Cells, Cultured; D002999:Clone Cells; D015672:Erythroid Precursor Cells / Q000166:cytology; D004921:Erythropoietin / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology; D007700:Kinetics; D017493:Leukocyte Common Antigens / Q000032:analysis; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology; D011990:Receptors, Transferrin; D019089:Stem Cell Factor / Q000494:pharmacology
D015703:Antigens, CD; D018952:Antigens, CD34; D000944:Antigens, Differentiation, B-Lymphocyte; C068126:CD71 antigen; D015850:Interleukin-6; D011990:Receptors, Transferrin; D019089:Stem Cell Factor; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor; D017493:Leukocyte Common Antigens