Normal human peripheral blood cells were unstimulated (left) or stimulated with Anti-Human CD3 Functional Grade Purified (Product # 16-0037-81) and Anti-Human CD28 Functional Grade Purified (Product # 16-0289-81) overnight (right) and then fixed and permeabilized with the Foxp3/Transcription Factor Staining Buffer Set (Product # 00-5523-00). Cells were intracellularly stained with Anti-Human CD20 FITC (Product # 11-0209-42) and Anti-Human E4BP4 (NFIL3) PE. Viable cells, as determined by staining with Fixable Viability Dye eFluor® 780 (Product # 65-0865-14), in the lymphocyte gate were used for analysis.