Confocal microscopy of double-labeled eosinophils. (A to C) Representative unstimulated eosinophils with the FITC channel corresponding to IL-6 (A), the Texas Red channel corresponding to MBP (B), and the combined fluorescence (C). (D to E) Isotype controls for FITC fluorescence and Texas Red fluorescence, respectively. (F) Close-up of granules from an unstimulated cell showing doughnut-shaped IL-6 immunoreactivity surrounding red centers of MBP immunoreactivity. (G to J) Time course of IFNγ effects on IL-6 immunoreactivity in eosinophils after (G) 10 minutes, (H) 6 hours, (I) 12 hours, and (J) 18 hours of stimulation by 500 U/mL IFNγ. (K to N) Same time course as G to J, showing combined images for IL-6 and MBP (original magnification ×100).