IL-3 specifically inhibits GM-CSF binding to the higher affinity receptor.
The inhibition of binding between human granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor by human interleukin-3 (IL-3) was observed in myelogenous leukemia cell line KG-1 which bore the receptors both for GM-CSF and IL-3. In contrast, this phenomenon was not observed in histiocytic lymphoma cell line U-937 or in gastric carcinoma cell line KATO III, both of which have apparent GM-CSF receptor but an undetectable IL-3 receptor. In KG-1 cells, the cross-inhibition was preferentially observed when the binding of GM-CSF was performed under the high-affinity binding condition; i.e., a low concentration of 125I-GM-CSF was incubated. Scatchard analysis of 125I-GM-CSF binding to KG-1 cells in the absence and in the presence of unlabeled IL-3 demonstrated that IL-3 inhibited GM-CSF binding to the higher-affinity component of GM-CSF receptor on KG-1 cells. Moreover, a chemical cross-linking study has revealed that the cross-inhibition of the GM-CSF binding observed in KG-1 cells is specific for the beta-chain, Mr 135,000 binding protein which has been identified as a component forming the high-affinity GM-CSF receptor existing specifically on hemopoietic cells.
Taketazu
F
F
Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Chiba
S
S
Shibuya
K
K
Kuwaki
T
T
Tsumura
H
H
Miyazono
K
K
Miyagawa
K
K
Takaku
F
F
D001667:Binding, Competitive; D002460:Cell Line; D003432:Cross-Linking Reagents; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D006801:Humans; D007377:Interleukin-3 / Q000502:physiology*; D007457:Iodine Radioisotopes; D007700:Kinetics; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D016185:Receptors, Interleukin-3 / Q000378:metabolism
D003432:Cross-Linking Reagents; D007377:Interleukin-3; D007457:Iodine Radioisotopes; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016185:Receptors, Interleukin-3; D016178:Granulocyte-Macrophage Colony-Stimulating Factor