Isolated DVs activate the alternative complement pathway. (A) Addition of isolated DVs to serum in the presence of EGTA/Mg dose-dependently provoked complement consumption (as assessed with rabbit erythrocytes) and C3 turnover. (B) Concentration of fluid-phase SC5b-9 in serum spiked with increasing numbers of isolated DVs. (C) Staining of C3 on isolated DVs after incubation with serum. Top row shows the controls, which were incubated in inactive serum; bottom row, cells incubated in active serum. (D) Detection of C5b-9 on DVs after incubation with active human serum. Corresponding flow cytometric analysis shows staining of all DVs in the sample. Representative results of 4 independent experiments are shown.