Vitronectin bound to intact bacteria inhibits C5b-9 deposition.

<p>Vitronectin (25–50 μg/ml) was bound to Hib (<i>A</i>), NTHi (<i>B</i>), <i>M</i>. <i>catarrhalis</i> (<i>C</i>) or <i>P</i>. <i>aeruginosa</i> (<i>D</i>), and after extensive washing C5b-6 and C7 were added. After incubation for 10 min, C8 and C9 were added, and thereafter C5b-9 deposition on the microbial surface was detected with a mouse anti-C5b-9 mAb and Alexa 647-conjugated anti-mouse pAb by flow cytometry. E, vitronectin (50 μg/ml) was bound to immobilized proteins, and after extensive washing C5b-6 and C7 were added. After 10 min incubation, C8 and C9 were added, and C5b-9 deposition was detected with a mouse anti-C5b-9 mAb and an HRP-conjugated anti-mouse polyclonal antiserum. The mean values from three independent experiments are shown with error bars indicating SD. **, <i>p</i> ≤ 0.01; ***, <i>p</i> ≤ 0.001.