Normal IgE/antigen-induced FcϵRI aggregation in PigA-deficient BMMCs. BMMCs were sensitized with IgE anti-DNP, and either left in medium (-Ag) or challenged with DNP-BSA antigen (+Ag) for 3 minutes, fixed and stained with fluorescent anti–mouse IgG(H+L). (A) Confocal microscope images show the appearance of FcϵRI aggregates at the upper cell surface after antigen challenge (+Ag) in both control (WT; top panels) and PigA-deficient BMMCs (KO; bottom panels). (B) Quantification of the number of FcϵRI aggregates per cell by the Particle Analysis software. Shown are the mean numbers ± SEM particles per cell, as a measure for FcϵRI aggregation, of at least 15 cells per group. Filled bars: littermate control BMMC; open bars: PigA-deficient BMMCs. Asterisk indicates significant difference (P < .05) with control cells; n.s. indicates not significant.