Diagnostic assay for inhibitor of tissue-type and urokinase-type plasminogen activators, and gene coding for the inhibitor

A solid phase assay method for detecting the presence of endothelial plasminogen activator inhibitor in a liquid sample to be assayed comprising the steps of:

• (a) providing a solid phase support comprising a solid matrix to which is affixed substantially pure, recombinant human endothelial plasminogen activator inhibitor, said recombinant inhibitor being substantially free of glycosylation, inhibiting the activities of both t-PA and u-PA, being immunologically different from protease nexin and placental plasminogen activator inhibitor, having the amino acid residue sequence of FIG. 22 from amino acid residue position 1 through position 379 and exhibiting an apparent relative molecular mass of about 40 kilodaltons in SDS-PAGE analysis;
• (b) admixing an aliquot of said liquid sample to be assayed with a predetermined amount of antibodies that specifically bind to both said recombinant inhibitor of said solid support and the inhibitor to be assayed to form an admixture;
• (c) maintaining said admixture under biological assay conditions for a predetermined period of time sufficient for the antibodies to bind to inhibitor present in the sample;
• (d) admixing said maintained admixture with said solid support to form a solid-liquid phase admixture;
• (e) maintaining said solid-liquid phase admixture under biological assay conditions for a predetermined time period sufficient for antibodies of the admixture not bound to inhibitor of the sample to bind the recombinant inhibitor of the solid support;
• (f) separating the solid and liquid phases;
• (g) determining the amount of antibodies bound to the recombinant inhibitor bound to the solid support, and thereby the amount of inhibitor in the sample assayed.