1997 Volume 121 Issue 5 Pages 896-901
The two interleukin 1 precursors (preIL-1αla and β) with a molecular mass of 33 kDa are proteolytically processed to the mature carboxyl-terminal 17-kDa proteins. In this study we newly developed a monoclonal antibody against the precursor domain of IL-1β(ED7), of which the binding to preIL-1β was hindered by a polyclonal antibody against the mature domain of IL-1β Immunoprecipitation of limited proteolysed preIL-1β by ED7 suggested that the epitope for ED7 may not be localized at the junction between preIL-1β and mature IL-1β. We therefore examined the possibility that the pre-domain of IL-1β might interact with the mature domain by using chemical cross-linking. V8 protease yielded a mature 17. 5-kDa protein from untreated preIL-1β but not chemically cross-linked preIL-1β However, cleavage of the cross-link with 2-mercaptoethanol liberated a mature 17. 5-kDa protein from preIL-1β, suggesting that the pre-domains of IL-1β might interact with the mature domain. Similar phenomena were observed with preIL-1α Such an intermolecular interaction may inhibit or modulate the biological activity of mature IL-1s.
