1X10^6 PMA (50 ng/ml) and ionomycin (1 ug/ml)-stimulated human PBMCs (5 hours) were surface stained with 0.2 ug Anti-Human CD154 (65156-1-Ig, Clone: 24-31) and FITC anti-mouse IgG1 Antibody at dilution 1:200 (green), or stained with 0.2 ug isotype control and FITC anti-mouse IgG1 Antibody at dilution 1:200 (black). Cells were not fixed.