1X10^6 mouse splenocytes were surface stained with CoraLite® Plus 647 Anti-Mouse CD4 (GK1.5) (CL647-65104, Clone: GK1.5) and 0.13 ug FITC Plus Rat IgG1 isotype control (left) or 0.13 ug FITC Plus Anti-Mouse CD25 (FITC-65137, Clone: PC61.5) (right). Cells were not fixed.