The influence of antibodies to HK-binding proteins on HUVEC membranes on urokinase-induced plasminogen activation.

Microtiter plate wells with a confluent monolayer of HUVEC were incubated with plasminogen (PLG; 1 μM) for 1 hour at 37°C. After incubation, the cells were washed and the initial rate of formed plasmin was determined by the addition of 2 nM ProUK and 0.3 mM S2251. In other experiments, the HUVEC monolayer was incubated with 20 nM HK and PK for 1 hour at 37°C in the absence or presence of 350 nM anti-GPV20, 60 nM anti-uPAR, 100 nM anti-gC1qR, 350 nM goat IgG, or 100 nM mouse IgG. At the end of the incubation, the cells were washed and incubated with plasminogen for another hour at 37°C. After washing the cells again, the initial rate of formed plasmin was determined by the addition of 2 nM ProUK and 0.3 mM S2251. The data are expressed as the percent plasmin formed when compared to the assembly of HK, PK, plasminogen, and ProUK. The data shown are the mean ± SEM of 3 experiments.