INACTIVATION OF C1-BAR INHIBITOR BY PROTEASES - DEMONSTRATION BY A MONOCLONAL-ANTIBODY OF A NEODETERMINANT ON INACTIVATED, NON-COMPLEXED C1-BAR INHIBITOR

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  • 1 July 1987
    • journal article
    • research article
    • Vol. 61  (3) , 387-389
Abstract
Monoclonal antibodies were raised against kallikrein-C.hivin.1 inhibitor and factor XIIa-C.hivin.1 inhibitor complexes. One of the monoclonal antibodies (KII) appeared to react predominantly with C.hivin.1 inhibitor complexes in an ELISA. However, the apparent binding of KII to C.hivin.1 inhibitor complexes was probably due to the presence of proteolytically inactivated C.hivin.1 inhibitor in the complex mixture used for the coating: KII did not bind either kallikrein-C.hivin.1 inhibitor or factor XIIa-C.hivin.1 inhibitor complexes generated in plasma by dextran sulphate. SDS-PAGE analysis of C.hivin.1 inhibitor incubated with proteases revealed that KII-reactive C.hivin.1 inhibitor has a lower molecular weight than native C.hivin.1 inhibitor. We propose that the determinant that reacts with KII is exposed after cleavage of C.hivin.1 inhibitor in its reactive site. The monoclonal antibody KII will enable us to study the inactivation of C.hivin.1 inhibitor in human inflammatory disease.