A urine inhibitor of interleukin 1 activity that blocks ligand binding
Seckinger, P.; Lowenthal, J.W.; Williamson, K.; Dayer, J.M.; MacDonald, H.R.
Journal of Immunology 139(5): 1546-1549
1987
ISSN/ISBN: 0022-1767 PMID: 2957429 Document Number: 288031
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.