Percent of phagocytosis for human E containing varying amounts of bound rabbit IgG. E were consecutively opsonized with varying amounts of human anti-(D) Rho antibodies followed by a mouse MoAb (HB 43) specific for human IgG followed by rabbit antimouse IgG. Alternatively, the E were biotinylated (b-E), and then consecutively treated with SA, biotinylated mouse MoAb 4-15, and rabbit antimouse IgG. In the third model, the E were first opsonized with various anti-CR1 MoAbs followed by rabbit antimouse IgG. Finally, the two single points (⊡) represent nonbiotinylated E that were consecutively treated with biotinylated anti-CR1 MoAb 7G9, followed by SA, biotinylated MoAb 4-15, and finally by rabbit antimouse IgG. The graph portrays the results for multiple independent studies. The oval demonstrates the background level of phagocytosis for E treated with BSA-PBS followed by rabbit antimouse IgG. The solid circle at 2,732 IgG/E is also reported in Fig 2.