Specific binding of radioiodinated granulocyte-macrophage colony-stimulating factor to hemopoietic cells.
The hemopoietic growth factor granulocyte-macrophage colony-stimulating factor, GM-CSF, specifically controls the production of granulocytes and macrophages. This report describes the binding of biologically-active 125I-labeled murine GM-CSF to a range of hemopoietic cells. Specific binding was restricted to murine cells and neither rat nor human bone marrow cells appeared to have surface receptors for 125I-labeled GM-CSF. 125I-Labeled GM-CSF only appeared to bind specifically to cells in the myelomonocytic lineage. The binding of 125I-labeled GM-CSF to both bone marrow cells and WEHI-3B(D+) was rapid (50% maximum binding was attained within 5 min at both 20 degrees C and 37 degrees C). Unlabeled GM-CSF was the only polypeptide hormone which completely inhibited the binding of 125I-labeled GM-CSF to bone marrow cells, however, multi-CSF (also called IL-3) and G-CSF partially reduced the binding of 125I-labeled GM-CSF to bone marrow cells. Interestingly, the binding of 125I-labeled GM-CSF to a myelomonocytic cell line, WEHI-3B(D+), was inhibited by unlabeled GM-CSF but not by multi-CSF or G-CSF. Scatchard analysis of the binding of 125I-labeled GM-CSF to WEHI-3B(D+) cells, bone marrow cells and peritoneal neutrophils indicated that there were two classes of binding sites: one of high affinity (Kd1 = 20 pM) and one of low affinity (Kd2 = 0.8-1.2 nM). Multi-CSF only inhibited the binding of 125I-labeled GM-CSF to the high affinity receptor on bone marrow cells: this inhibition appeared to be a result of down regulation or modification of the GM-CSF receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
Walker
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Burgess
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D000818:Animals; D001667:Binding, Competitive; D001853:Bone Marrow / Q000378:metabolism*; D002460:Cell Line; D003115:Colony-Stimulating Factors / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D051379:Mice; D008970:Molecular Weight; D011956:Receptors, Cell Surface / Q000378:metabolism*; D016184:Receptors, Colony-Stimulating Factor; D012016:Reference Values
D003115:Colony-Stimulating Factors; D011956:Receptors, Cell Surface; D016184:Receptors, Colony-Stimulating Factor