title: Characterization of hemopoietic cell populations from human cord blood expressing c-kit.
abstract: Human cord blood or bone marrow cells expressing the CD34 surface antigen include a population of pluripotent progenitors. We identified and isolated a subpopulation of cells coexpressing CD34 and c-kit, a transmembrane receptor with tyrosine kinase activity. Novel monoclonal antibodies (16A6, 14A3, 3D6) directed against the extracellular domain of c-kit were used for immunofluorescence labeling and sorting of low-density mononuclear cells (MNCs) from umbilical cord blood and bone marrow. The frequency of c-kit-labeled MNCs from cord blood (mean 5.0% +/- 2.1%, n = 16) was similar to that from adult bone marrow (mean 3.7% +/- 1.3%, n = 4). On average, 1.4% of CD34-positive cells were recorded in cord blood and 2.1% in bone marrow MNCs. Roughly 60% of CD34-positive cells coexpressed c-kit. The ability of CD34+/c-kit+ cells to form multilineage colonies (CFU-GEMM) was assayed after sorting with an antibody that did not show any significant effect on c-kit ligand (RL) or granulocyte/macrophage colony-stimulating factor (GM-CSF)-induced colony formation. For CD34+/c-kit+ cells, we found a 20- to 50-fold enrichment as against total MNCs, and a 2-fold enrichment if compared with the CD34+/c-kit-population. To study expression of c-kit in lymphocytic precursors, monoclonal anti-CD7 or anti-CD10 antibodies were used simultaneously. In contrast to CD34-expressing cells, however, no consistent double-labeled subpopulation of lymphocytic cells was detected. Furthermore, coexpression of CD38 (73% +/- 14%, n = 4) or CD33 (29% +/- 12%, n = 5) on a majority of c-kit-positive cells showed their lineage commitment to erythropoiesis and granulocytopoiesis.
authors.affiliation: GSF-Institute of Experimental Hematology, Munich, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Reisbach
authors.forename: I
authors.initials: I
authors.lastname: Bartke
authors.forename: B
authors.initials: B
authors.lastname: Kempkes
authors.forename: G
authors.initials: G
authors.lastname: Kostka
authors.forename: J
authors.initials: J
authors.lastname: Ellwart
authors.forename: A
authors.initials: A
authors.lastname: Birner
authors.forename: K
authors.initials: K
authors.lastname: Thalmeier
authors.forename: R
authors.initials: R
authors.lastname: Mailhammer
authors.forename: G W
authors.initials: GW
authors.lastname: Bornkamm
authors.forename: A
authors.initials: A
authors.lastname: Ullrich
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis*; D018952:Antigens, CD34; D000943:Antigens, Differentiation / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001402:B-Lymphocytes / Q000378:metabolism; D001854:Bone Marrow Cells; D002469:Cell Separation; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000166:cytology; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000276:immunology; D019009:Proto-Oncogene Proteins c-kit; D063268:Sialic Acid Binding Ig-like Lectin 3; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D063268:Sialic Acid Binding Ig-like Lectin 3; D019009:Proto-Oncogene Proteins c-kit; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1