A ONE-STEP ENZYME-IMMUNOASSAY FOR THE DETERMINATION OF TOTAL TISSUE-TYPE PLASMINOGEN-ACTIVATOR (T-PA) ANTIGEN IN PLASMA

A reproducible and sensitive one-step enzyme immunoassay (EIA) was developed to determine total tissue-type plasminogen activator (t-PA) antigen in plasma. The EIA comprises two monoclonal catching antibodies and a polyclonal (goat) tagging antibody conjugated with horseradish peroxidase. There is an equal reactivity towards the several physiological t-PA forms, i.e., single-chain t-PA, two-chain t-PA and t-PA in complex with its naturally occurring inhibitor plasminogen activator inhibitor-type 1 (t-PA/PAI-1 complex). Additionally, the EIA does not discriminate between human melanoma t-PA and recombinant t-PA (Activase). The assay has a lower detection limit of approximately 0.5 ng t-PA per ml plasma, with a time-to-result of only 3.5 h.