Normal human peripheral blood cells were unstimulated (left) or stimulated for 72 hours with CD3 and CD28 Monoclonal Antibodies, Functional Grade (Product # 16-0037-85 and 16-0289-85) (right). Cells were then stained with CD25 Monoclonal Antibody, PE (Product # 12-0259-42) and CD357 (AITR/GITR) Monoclonal Antibody, APC-eFluor 780. Total viable cells, as determined by Fixable Viability Dye eFluor® 506 (Product # 65-0866-14), were used for analysis.