title: A urine inhibitor of interleukin 1 activity that blocks ligand binding.
abstract: Urine from febrile patients was found to contain a novel inhibitor of interleukin 1 (IL-1) bioactivity that blocked the specific binding of radioiodinated IL-1 to its receptor in a dose-dependent fashion. Strong inhibition of IL-1 binding was still obtained when cells were preincubated with the inhibitor and washed, thus suggesting that the inhibitor binds to a surface structure (possibly the IL-1 receptor itself). The inhibitor was distinct from IL-1 as determined by both physical parameters (size and antigenicity) and receptor-binding characteristics (apparent affinity and dissociation rate). These data provide evidence for a physiologic regulator of IL-1 activity that functions in vivo via direct interference with ligand binding.
mesh_terms: D000818:Animals; D002460:Cell Line; D005334:Fever / Q000652:urine; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D051379:Mice; D011485:Protein Binding / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology*; D011971:Receptors, Immunologic / Q000378:metabolism; D017472:Receptors, Interleukin-1; D015375:Receptors, Interleukin-2; D012795:Sialoglycoproteins; D013945:Thymoma / Q000473:pathology
chemical_list: C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D007376:Interleukin-2; D011506:Proteins; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; D015375:Receptors, Interleukin-2; D012795:Sialoglycoproteins