BALB/c mouse splenocytes were unstimulated (left) or stimulated for 72 hours with Con A (Product # 00-4978-03) (right). Cells were then stained with CD25 Monoclonal Antibody, Alexa Fluor 488 (Product # 53-0251-82) and 0.25 µg of CD278 Monoclonal Antibody, Super Bright 436. Total viable cells were used for analysis, as determined by Fixable Viability Dye eFluor 660 (Product # 65-0864-18).