Fetal bone marrow CD34+CD41+ cells are enriched for multipotent hematopoietic progenitors, but not for pluripotent stem cells.
We have investigated the expression of CD41a (gpIIbIIIa) on a subpopulation of human fetal bone marrow (FBM) CD34+ progenitor cells. Human FBM CD34+Lin- cells were subfractionated into CD41a+ and CD41a- subpopulations by flow cytometry. All the megakaryocyte colony-forming cells (CFU-MK) and almost all the burst-forming units-megakaryocyte (BFU-MK) were found within the CD41a+ subpopulation. In addition, a 14-fold greater number of granulocyte-macrophage colony-forming units (CFU-GM) and a five-fold greater number of mixed lineage progenitor cells (CFU-mix) were observed within the CD34+Lin-CD41a+ subpopulation compared to the CD34+Lin-CD41a- subpopulation. The high proliferative potential of CD34+Lin-CD41a+ cells was demonstrated by their capacity to expand in in vitro culture containing human plasma and recombinant Mpl ligand (thrombopoietin [Tpo]) with production of over 80% CD41b+ (gpIIb+) MKs. However, in long-term bone marrow cultures, the CD34+Lin-CD41a- population contained a significantly higher frequency of cobblestone area-forming cells (CAFC) than the CD34+Lin-CD41a+ population, indicating the presence of a primitive hematopoietic stem cell (HSC) population within the CD34+Lin-CD41a- subset. These data suggest that fetal CD34+Lin-CD41a+ cells are enriched for MK progenitor cells (CFU-MK and BFU-MK), myeloid progenitors, and CFU-mix but do not contain the more primitive CAFC.
Murray
L J
LJ
SyStemix Inc., Palo Alto, CA 94304, USA.
Mandich
D
D
Bruno
E
E
DiGiusto
R K
RK
Fu
W C
WC
Sutherland
D R
DR
Hoffman
R
R
Tsukamoto
A
A
D018952:Antigens, CD34 / Q000032:analysis; D001853:Bone Marrow / Q000196:embryology*; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D019070:Cell Lineage; D002469:Cell Separation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006801:Humans; D016130:Immunophenotyping; D008533:Megakaryocytes / Q000166:cytology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000032:analysis; D013234:Stem Cells / Q000145:classification* / Q000166:cytology; D013926:Thrombopoietin / Q000032:analysis
D018952:Antigens, CD34; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D013926:Thrombopoietin