ENZYME-LINKED IMMUNOSORBENT ASSAYS FOR PLASMINOGEN ACTIVATORS

ELISA procedures are described for the quantitative analysis of the ur okinase-type plasminogen activator (uPA) and of the tissue type PA (tP A). The assays were developed to detect the respective type of PA in c ell culture supernatants. TPA can be present as a single-chain or a tw o-chain protein; uPA as pro-uPA, high or low molecular weight uPA, res pectively. In addition, both PAs can be complexed with the plasminogen activator inhibitors PAI-I or PAI-2. Monoclonal antibodies specific f or uPA or tPA were selected that recognized the distinct molecular for ms of the PAs, even in the presence of fetal calf serum, which is a co mmon - relatively ill-defined - ingredient of cell culture media. The test systems were found to be reliable, easy to perform, and to permit the detection of both types of PA in serum-free and serum-containing cell culture supernatants. Finally, the ELISA - in combination with fu nctional tests - were used to analyse the different PA components in c ulture supernatants of uPA- or tPA-producing cell lines.