Phagocytosis mediated by Fcγ-R. (A) Time course of phagocytosis of IgG-coated, FITC-labeled E coli by CD14-positive peripheral blood monocytes (PBM) isolated from 4 WAS patients (W-BL, W-SS, W-JG, W-SG; open bars) or from normal controls (filled bars). (B) Efficiency of phagocytosis by WAS PBM compared to normal control PBM. Pooled values from the 4 WAS patients are expressed as a percentage of pooled values from the normal controls. (C) Phagocytosis by normal (filled bars) and WAS (open bars) PBM, 15 minutes after addition of different amounts of IgG-coated, FITC-labeledE coli. WAS PBM were from patient W-SS. Cell type specificity of internalization was confirmed by demonstrating a negligible rate of uptake of IgG-coated, FITC-labeled E coli by the CD14⁻ lymphocyte population (data not shown). Treatment of PBM with 10 mmol/L cytochalasin D for 30 minutes abrogated uptake of IgG-coated, FITC-labeled E coli to background levels (data not shown).