Biological activity of human urine IL-1 inhibitor

Abstract

Properties of IL-1 inhibitor present in the urine of febrile patients were examined. The molecular weight of IL-1 inhibitor was estimated to be about 21 KD by high pressure liquid chromatography (HPLC). IL-1 inhibitor was inactivated by incubation at 56°C for 30min or treatment with acid at pH3.0, but its activity was not affected at pH5_??_11. It was also unaffected by treatment with neuraminidase.
IL-1 inhibitor suppressed not only thymocyte proliferation induced by IL-1 but also in vitro plaque forming cell (PFC) formation and the development of fever after intraperitoneal administration of IL-1 in mice. These data suggest that IL-1 inhibitor acts not only in vitro but also in vivo.