Characterization of a receptor for interleukin-5 on human eosinophils and the myeloid leukemia line HL-60.
Interleukin-5 (IL-5) promotes the growth and differentiation of human eosinophils and may regulate the selective eosinophilia and eosinophil activation seen in certain diseases. Radiolabeled recombinant human IL-5 (hIL-5) was used to characterize the IL-5 receptor present on normal human eosinophils and on the myeloid leukemia line HL-60, which can be induced to differentiate into eosinophilic cells. Binding studies with eosinophils and HL-60 cells grown under alkaline conditions demonstrated similar high-affinity binding sites for hIL-5 on both cell types with kd values of approximately 400 pmol/L. The binding observed was specific in that it was not inhibited by hIL-3, human granulocyte-macrophage colony-stimulating factor, or hIL-2. Binding studies with a number of other human cell lines, including a B-lymphoma line, and with lymphocyte and neutrophil preparations were also performed, but IL-5 receptors were not detectable on these cells. The number of hIL-5 receptors on HL-60 cells could be correlated with its propensity to differentiate towards an eosinophilic cell type. Expression of hIL-5 receptors on HL-60 cells was upregulated by butyric acid under alkaline conditions, downregulated by hIL-3, virtually eliminated by dimethyl sulfoxide and hIL-5, while hIL-2 had no detectable effect. One major 125I-hIL-5-crosslinked complex of 75 to 85 Kd in Mr was detected on HL-60 cells using crosslinking agents giving a molecular mass of 55 to 60 Kd for the hIL-5 receptor itself. Studies using cellular autoradiography showed that IL-5 receptors were evenly distributed on eosinophils but that receptor distribution on HL-60 cells was noticeably heterogeneous. Eosinophils were the only cells in slides prepared from peripheral blood that had detectable levels of IL-5 receptors in agreement with the specific action of IL-5 on the human eosinophil lineage.
Ingley
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Medical Molecular Biology Group, John Curtin School of Medical Research, Australian National University, Canberra.
Young
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D001345:Autoradiography; D001667:Binding, Competitive; D002460:Cell Line; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D004804:Eosinophils / Q000276:immunology*; D006801:Humans; D015848:Interleukin-5 / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute; D008214:Lymphocytes / Q000276:immunology; D008970:Molecular Weight; D009504:Neutrophils / Q000276:immunology; D011971:Receptors, Immunologic / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins / Q000378:metabolism; D013816:Thermodynamics
D015848:Interleukin-5; D007457:Iodine Radioisotopes; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins