Plasminogen inhibits monocyte apoptosis in a dose-dependent manner. Human monocytes were cultured in the absence of an apoptotic inducer (A,D, untreated cells) or with the addition of 10 ng/mL TNFα (B,E) or 50 μg/mL cycloheximide (C,F) for 24 hours to induce apoptosis. In panels D, E, and F, 2 μM plasminogen was added simultaneously with the apoptotic inducers. The cells were analyzed by flow cytometry using annexin V–FITC and PI. The numbers in each quadrant indicate the percentage of the total cell population.