Figure 1.

Western blot of human neutrophil lysate before and after FcγRIII immunoprecipitation. The identity of FcγRIIIb was confirmed with an anti-CD16 antibody. The flow-through lanes show the diluted unbound fraction of the immunoprecipitation, while the eluate lanes present the purified FcγRIIIb protein. The neutrophils lanes represent ∼25 μg of total protein content from the neutrophil cell lysate from donor 2. Apparent differences in the western blot are due to concentration differences. The weaker signal of extremely low and high MW proteoforms is lost at lower concentrations after IP. The cropping area is indicated by dashed lines. The complete gel and blot are presented in Figures S1 and S2.