1X10^6 unstimulated or PMA and ionomycin stimulated (in the presence of protein transport inhibitors) mouse Th2-polarized splenocytes were surface stained with 0.2 ug PE Anti-Mouse CD4 (GK1.5) (PE-65104, Clone: GK1.5). Cells were fixed with 4% PFA and permeabilized with Flow Cytometry Perm Buffer (PF00011-C), and then intracellularly stained with 0.5 ug APC Anti-Mouse IL-4 (APC-65074, Clone:11B11).