The flt3/flk-2 ligand: Receptor distribution and action on murine haemopoietic cell survival and proliferation
Details
Publication Year 1995-12-01,Volume 9,Issue #12,Page 2058-2066
Journal Title
LEUKEMIA
Publication Type
Journal Article
Abstract
In this study the distribution and quantitation of the flt3/flk-2 receptor was examined on bone marrow cells and defined haemopoietic subpopulations. Undifferentiated cells expressed the greatest numbers of flt3/flk-2 receptors: 19% of primitive lin(-)kit(+)sca-1(+) bone marrow cells and 16% of fetal liver lin(-)aa4.1(+) cells exhibited over 15 000 receptors per cell as determined by binding of the radiolabeled cognate ligand (flt3/flk-2 ligand, FL). Moderate binding was demonstrated on early B lymphocyte subsets (4400 receptors per cell) and very low levels were detected on monocytes. Binding was not detected on promyelocytes, myelocytes, promonocytes, metamyelocytes, polymorphonuclear cells, eosinophils or nucleated erythroid cells. FL enhanced the survival of primitive lin(-)kit(+)sca-1(+) cells with an efficacy equivalent to stem cell factor (SCF). FL stimulated predominantly blast and granulocyte-macrophage colony formation in cultures of bone marrow cells by both direct and indirect mechanisms. Marked synergistic effects of FL with combinations of colony stimulating factors (CSFs) or interleukin-6 occurred on the proliferation of primitive lin(-)kit(+)sca-1(+) cells, but not lin(-)kit(+)sca-1(-) progenitor cells. Surprisingly, recloning experiments revealed that FL plus IL-3 increased the generation of progenitor cells by lin(-)kit(+)sca-1(-) cells compared with SCF plus 11-3. Thus FL functions as a factor with both direct and indirect stimulatory activities directed to the expansion, maintenance of clonogenic potential, and possibly limited self-renewal, of early haemopoietic cells.
Publisher
STOCKTON PRESS
Keywords
HEMATOPOIETIC STEM-CELLS; COLONY-STIMULATING FACTORS; TYROSINE KINASE RECEPTOR; BONE-MARROW; TRANSGENIC MICE; CDNA CLONING; C-KIT; GENE; EXPRESSION; FAMILY
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Creation Date: 1995-12-01 12:00:00
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