Figure 3. PMN-mediated ADCC is restored by blockade of FcγRIII. In ADCC experiments against A431 cells, PMN from healthy donors were effective with wild type, but not with S239D/I332E mutated anti-EGFR antibody (left panels), while MNC-mediated killing was enhanced with Fc-engineered compared with wild type antibodies (right panels). (A) FcγRIII blockade by anti-CD16 but not by the control antibody restored PMN-mediated ADCC activity (left panel) but impaired MNC-mediated ADCC activity (right panel) triggered by both antibody variants. (B) FcγRII blockade by anti-CD32 almost completely abolished PMN-mediated ADCC activity (left panel) for both antibody variants but did not affect MNC-mediated ADCC activity (right panel). Data are presented as mean ± SEM from three independent experiments with different blood donors. * P ≤ 0.05