Characterization of a receptor for interleukin 5 on human eosinophils: variable expression and induction by granulocyte/macrophage colony-stimulating factor.
Interleukin 5 (IL-5) acts on eosinophil differentiation and activation, suggesting the existence of a membrane receptor for IL-5 on eosinophils. Here, we report that 125I-labeled recombinant human IL-5 bound, at 4 degrees C, to high affinity receptors on human eosinophils. The association constant was higher for hypodense eosinophils (1.93 x 10(9) M-1) than for normodense cells (0.39 x 10(9) M-1), with a closely related number of receptor sites per cell. No specific binding occurred on neutrophils. The specific binding of IL-5 was induced by overnight incubation at 37 degrees C of human eosinophils with granulocyte/macrophage (GM)-CSF. The levels of increase were significantly higher for normodense than for hypodense eosinophils, suggesting a previous in vivo activation of the later subpopulation by GM-CSF. IL-3 was ineffective by itself but synergistically enhanced the effect of GM-CSF. Specificity studies showed that the binding of 125I-labeled IL-5 was inhibited by IL-5, but not by other cytokines, on human eosinophils. These results show the existence of a specific binding site for IL-5 on human eosinophils with a variable affinity on eosinophil hypodense or normodense subpopulations, as previously reported for other membrane receptors.
Chihara
J
J
Centre d'Immunologie et de Biologie Parasitaire, Unité Mixte INSERM U167, CNRS 624, Institut Pasteur, Lille, France.
Plumas
J
J
Gruart
V
V
Tavernier
J
J
Prin
L
L
Capron
A
A
Capron
M
M
D002478:Cells, Cultured; D004804:Eosinophils / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D005786:Gene Expression Regulation / Q000187:drug effects; D014644:Genetic Variation / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D015848:Interleukin-5 / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins / Q000378:metabolism
D007377:Interleukin-3; D015848:Interleukin-5; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor