summary
Two different monoclonal antibodies against the heparin- dependent inhibitor of human
activated protein C were produced, using cleaved modified inhibitor for immunization
and partially purified inhibitor for screening of the hybridomas, One of the antibodies
recognized free and complexed forms of the inhibitor in immunoblotting experiments.
The other antibody was used to develop an assay for A PC -PCI inhibitor complexes.
Using the assay the formation of complexes was studied in plasma, both in the presence
and absence of heparin. The rate of complex formation was similar to that reported
previously for the loss of activated protein C amidolytic activity in plasma. The
same antibody was also immobilized on Sepharose and used to purify the inhibitor from
fresh human plasma. The purified material appeared as two narrowly spaced bands with
Mr about 57,000 in SDS-PAGE. The average yield from 1 liter of fresh plasma was 1 mg
of inhibitor, The purified inhibitor formed SDS stable complexes with activated protein
G and urokinase that could be identified in immunoblots using specific antibodies.
Keywords
Protein C - Protein C inhibitor
