Figure 1.

Urokinase-type plasminogen activator (uPA) inhibits efferocytosis of apoptotic neutrophils. A total of 100, 300, 600, or 1,000 ng/ml human single-chain plasminogen activator (scuPA) or 1,000 ng/ml human serum albumin (HSA) was added to cultures of macrophages and apoptotic neutrophils. Phagocytosis assays were performed as described in the Methods section. Each condition included two independent samples and each sample was counted four times by a blinded observer. Data are shown as SD of the eight counts from each condition. * P < 0.05, ** P < 0.01, *** P < 0.001 compared with the group treated with HSA.