Identification of monoclonal antibodies that inhibit the function of protein C inhibitor. Evidence for heparin-independent inhibition of activated protein C in plasma

J. C. Meijers, R. A. Vlooswijk, D. H. Kanters, M. Hessing, B. N. Bouma

Research output: Contribution to JournalComment / Letter to the editorAcademic

9 Citations (Scopus)


Monoclonal antibodies specific for protein C inhibitor (PCI) partially blocked the inactivation of activated protein C (APC) in plasma, whereas in a purified system, the PCI activity could be completely blocked. The inactivation of APC in normal and in PCI-depleted plasma was similar in the absence of heparin. The addition of heparin did not change the rate of inactivation of APC in PCI-depleted plasma, whereas in normal plasma a rapid phase of inhibition of APC was followed by a slower phase of inhibition. The slower phase was identical to the rate of inhibition of APC in the absence of heparin. After incubation of normal plasma with a monoclonal antibody specific for PCI that blocked its activity, there was no difference in heparin-dependent or heparin-independent inhibition of APC. These results indicate that in the absence of heparin PCI is unable to inactivate APC in a plasma environment
Original languageEnglish
Pages (from-to)1401-1403
Issue number4
Publication statusPublished - 1988

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