title: Distribution of receptors for granulocyte-macrophage colony-stimulating factor on immature CD34+ bone marrow cells, differentiating monomyeloid progenitors, and mature blood cell subsets.
abstract: Biotin-labeled granulocyte-macrophage colony-stimulating factor (GM-CSF), in combination with phycoerythrin-conjugated streptavidin, enabled flow cytometric analysis of specific cell-surface GM-CSF receptors on rhesus monkey bone marrow (BM) and peripheral blood (PB) cells. GM-CSF receptors were readily detected on PB monocytes and neutrophils, but not on lymphocytes. In BM, GM-CSF receptors were identified on monocyte and neutrophil precursors and on subsets of cells that expressed the CD34 antigen. CD34+ cells with high GM-CSF-receptor expression coexpressed high levels of the class II major histocompatibility antigen RhLA-DR, whereas CD34+/RhLA-DRlow cells, which represent developmentally earlier cells, were either GM-CSF-receptor negative or expressed GM-CSF receptors at very low levels. The fluorescence histogram of CD34bright/RhLA-DRdull cells stained with biotin-GM-CSF showed that at least a fraction of these cells expressed low levels of GM-CSF receptors. CD34+ cells with high GM-CSF-receptor expression, purified by cell sorting, did not form colonies in culture or proliferate in response to GM-CSF. Instead, GM-CSF stimulation resulted in terminal differentiation into adherent cells, showing that these cells represented monocyte precursors. A distinct subset of CD34+ cells expressed GM-CSF receptors at low-to-intermediate levels and proliferated strongly in the presence of GM-CSF during short-term culture, but produced very few erythroid or monomyeloid colonies after longer culture periods. Most colony-forming cells, also those responsive to GM-CSF alone, were recovered in the subset of CD34+ cells on which GM-CSF receptors were virtually undetectable. These cells showed weaker proliferation in short-term proliferation assays than the CD34+/GM-CSF-receptor-intermediate cells, consistent with an immature phenotype. The results show that GM-CSF-receptor expression is initiated in a subset of immature, CD34bright/RhLA-DRdull cells and is progressively increased during differentiation into mature granulocytes and monocytes. The method used provides a new way to deplete developmentally early CD34+ cell of differentiating granulocyte and monocyte precursor cells.
authors.affiliation: Department of Hematology, Erasmus University, Rotterdam, The Netherlands.
authors.forename: A W
authors.initials: AW
authors.lastname: Wognum
authors.forename: Y
authors.initials: Y
authors.lastname: Westerman
authors.forename: T P
authors.initials: TP
authors.lastname: Visser
authors.forename: G
authors.initials: G
authors.lastname: Wagemaker
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D002469:Cell Separation; D005434:Flow Cytometry; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D008253:Macaca mulatta; D016177:Macrophage-1 Antigen / Q000032:analysis; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000949:Histocompatibility Antigens Class II; D016177:Macrophage-1 Antigen; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor