Quantitation of urokinase antigen in plasma and culture media by use of an ELISA.
An ELISA was set up using polyvinylchloride microtiter plates coated with rabbit anti-UK IgG's and affino-purified goat anti-UK IgG's as second antibody. Detection occurred with rabbit anti-goat IgG antibodies conjugated with alkaline phosphatase. The assay is specific for urokinase (UK) with a detection limit of 100 pg/ml sample. Tissue-type plasminogen activator, up to concentrations of 100 ng/ml, does not interfere. The assay measures the antigen of the inactive zymogen pro-UK, the active enzyme UK and the UK-inhibitor complex with equal efficiency and gives the total UK antigen present, irrespective of its molecular form. Culture media of fibroblasts, endothelial- and kidney cells showed, despite the absence of active UK, antigen levels of 1.2, 23 and 65 ng/ml, respectively. In human plasma the UK concentration was found to be 3.5 +/- 1.4 ng/ml (mean +/- SD, n = 54). The inter- and intra-assay variations were 20% and 6%, respectively.
D000818:Animals; D000906:Antibodies; D000936:Antigen-Antibody Complex; D001011:Aorta / Q000201:enzymology; D002294:Carcinoma, Squamous Cell / Q000201:enzymology; D002460:Cell Line; D002522:Chlorocebus aethiops; D003470:Culture Media; D004727:Endothelium / Q000201:enzymology; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007531:Isoflurophate / Q000494:pharmacology; D007668:Kidney; D008099:Liver / Q000201:enzymology; D008545:Melanoma / Q000201:enzymology; D012016:Reference Values; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000097:blood
D000906:Antibodies; D000936:Antigen-Antibody Complex; D003470:Culture Media; D007531:Isoflurophate; D014568:Urokinase-Type Plasminogen Activator