Complement activation occurs to completion on the surface of DVs but not on merozoites. (A) Late-stage pRBCs were cultured and allowed to rupture in the presence of 10% active human serum. Complement activity and hemolysis were recorded over time and found to be inversely correlated. Two-dimensional immunoelectrophoresis confirmed that C3 turnover occurred at the onset of hemolysis concomitant to the fall in complement activity (6 hours). Buffer controls (in the absence of pRBCs) are shown in the second row of panels. The bottom 2 plates show C3-immunoelectrophoresis at 0 and 8 hours from an experiment conducted with pRBCs in the presence of 10mM EGTA/2mM Mg²⁺. First-dimension electrophoresis is shown left to right and second-dimension immunoelectrophoresis bottom to top. (B) Synchronized late-stage pRBCs were allowed to rupture in active human serum, whereafter unlysed cells were pelleted and merozoites and DVs were harvested from the supernatants and stained for DNA or C5b-9. Top left is phase-contrast microscopy; top right, Hoechst 33342 DNA stain; bottom left, complement C5b-9 complex; bottom right, merge. Note selective staining of DVs for C5b-9.