FIGURE 7.
Effect of antibody blockade of endogenous Plg-RKT. A, non-transfected PC12 cells (3 × 105) were preincubated with 20 μg/ml of either anti-Plg-RKT mAb IgG (closed bars) or isotype control IgG (open bars) for 30 min at 37 °C) and then incubated with plasminogen (2.7 μm) for 30 min, and then t-PA (20 nm) was added and plasminogen activation was measured as cleavage of the tripeptide substrate d-VLK-pNA (1 mm) after 3 min. OD405 indicates optical density at 405 nm. B, non-transfected PC12 cells were preincubated with either anti-Plg-RKT mAb IgG (closed bars) or isotype control (open bars) for 30 min at 37 °C and then were treated with 60 μm nicotine (Nicotine) or buffer (Basal) at 37 °C for 15 min, and catecholamine release was measured by liquid scintillation counting as described under “Experimental Procedures.” The percentage of release was calculated as the percentage of secretion (amount released/(amount released + amount in cell lysate)), and results were expressed as net release (the percentage of secretagogue-stimulated release minus the percentage of basal release). Results are mean ± S.E., n = 6 for each experimental group. **, p < 0.001 for cells incubated with anti-Plg-RKT mAb when compared with isotype control.