Expression of high affinity receptors for murine interleukin 4 (BSF-1) on hemopoietic and nonhemopoietic cells.
In this report a method for the affinity purification and radiolabeling of recombinant mouse interleukin (IL)-4 is described. It is shown on the basis of several criteria that IL-4 retains full biologic activity after radioiodination and can therefore be used as a valid model for measuring the binding characteristics of native IL-4. By using Scatchard plot analysis of equilibrium binding data, it is demonstrated that 125I-IL-4 binds to a high affinity cell surface receptor which is expressed by both hemopoietic and nonhemopoietic cells. The dissociation constant for 125I-IL-4 (Kd = 20 to 60 pM) corresponds to the concentration of IL-4 which gives 50% biologic activity (i.e., 10 to 30 pM). Binding of 125I-IL-4 is rapid (t1/2 of 2 min), whereas dissociation occurs at a slow rate (t1/2 approximately 4 hr). The IL-4 receptor shows a high degree of specificity. Whereas unlabeled mouse IL-4 competed with mouse 125I-IL-4 in an equimolar fashion for binding to IL-4 receptors, several other lymphokines, including mouse IL-2, IL-3, interferon-gamma, granulocyte-macrophage colony-stimulating factor, and human IL-1, IL-2, and IL-4 were unable to inhibit, even at molar excesses of 400 to 800-fold. At 37 degrees C, 125I-IL-4 is rapidly internalized (approximately 200 molecules/cell/min) by HT-2 cells, with at least 85% of cell surface receptors being functional in this respect. Receptors for IL-4 were found to be expressed by subclasses of T and B cells, mast cells, macrophages, and by cells of the myeloid and erythroid lineages. This wide distribution of receptor expression closely matches the known spectrum of biologic activities of IL-4, including proliferation and/or differentiation of T and B cells, mast cells and granulocytes, and induction of macrophage antigen-presenting capacity. IL-4 receptors were also found on a variety of nonhemopoietic cells such as cloned stromal cell lines from the bone marrow, spleen, thymus, and brain, and on muscle, brain, melanoma, fibroblast, and liver cells. Indeed, only 5 of more than 90 cell types tested have undetectable numbers of IL-4 receptors. The biologic effects of IL-4 on nonhemopoietic cells have not yet been reported and await elucidation.
D000818:Animals; D002460:Cell Line; D005260:Female; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D015847:Interleukin-4; D007378:Interleukins / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D011869:Radioligand Assay / Q000379:methods; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000032:analysis* / Q000145:classification / Q000302:isolation & purification; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism; D014508:Urea / Q000031:analogs & derivatives
D007378:Interleukins; D007457:Iodine Radioisotopes; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; D015847:Interleukin-4; C012385:1,3,4,6-tetrachloro-3 alpha,6 alpha-diphenylglycoluril; D014508:Urea