FIGURE 1.
Plasminogen/plasmin promotes adherence to and internalization of S. pyogenes serotype M49 into human keratinocytes. A, measurement of plasmin enzymatic activity of different plasminogen-pretreated and -untreated S. pyogenes serotypes. The data represent the mean values ± S.D. from ten independent experiments. The y axis shows the A405 nm for each serotype. B, dot-blot analysis of plasminogen pretreated and untreated S. pyogenes serotype M49. Plasminogen (+) was used as a positive control and fibronectin (−) as a negative control. The data shown are representative of three independent experiments. Shown is the streptococcal adherence to (C) and internalization into (D) HaCaT cells after 2 h. The percentage of attached or internalized bacteria in the absence of plasminogen (none) was used as a control. To exclude the influence of plasmin serine protease effects aprotinin and α2-antiplasmin were used as inhibitors. The data represent the mean values ± S.D. from five independent experiments. Only significant differences are indicated (*, p < 0.05; **, p < 0.01; ***, p < 0.001).