Functional and biochemical characterization of mouse P40/IL-9 receptors.
The existence of saturable and specific binding sites for mouse P40/IL-9 was demonstrated on a variety of factor-dependent T cell lines derived from Th clones by long term culture in the presence of P40-containing T cell supernatants. Scatchard transformation of the data obtained with one such line was consistent with the existence of a single class of receptors with a Kd of approximately 100 pM and a density of 3000/cell. P40 binding to these cells was followed by rapid internalization of the ligand. P40-receptors (P40-R)3 were also found on certain Th clones maintained in conventional cultures, especially after stimulation with Ag and APC. Only T cell clones that proliferated in response to P40 showed significant levels of binding, suggesting that the regulation of P40-R expression is an important element in the control of P40-responsiveness. In accord with this idea, fresh T cells, cytolytic T cell clones and a wide variety of other cells including B cells and fibroblasts, which do not proliferate in response to P40, showed no significant binding. However, P40-R were not restricted to a few unusual Th clones. They were also detected on several T cell tumors, on macrophages and on mast cell lines. The latter point is of particular interest in view of the mast cell growth factor activity recently ascribed to P40. Cross-linking studies with T-cell lines and mast cells indicated that the P40-R consists of a 64-kDa glycoprotein, the molecular mass of which is reduced to 54 kDa on treatment with N-glycosidase F.
Druez
C
C
Unit of Experimental Medicine, University of Louvain, Brussels, Belgium.
Coulie
P
P
Uyttenhove
C
C
Van Snick
J
J
D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D004705:Endocytosis; D016906:Interleukin-9; D007378:Interleukins / Q000502:physiology*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000378:metabolism; D008407:Mast Cells / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D011971:Receptors, Immunologic / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D018123:Receptors, Interleukin; D053651:Receptors, Interleukin-9; D011994:Recombinant Proteins; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*; D014407:Tumor Cells, Cultured
D016906:Interleukin-9; D007378:Interleukins; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D053651:Receptors, Interleukin-9; D011994:Recombinant Proteins