1X10^6 plate-bound Anti-CD3 and Anti-CD28 stimulated mouse splenocytes were surface co-stained with CoraLite®488 Plus Anti-Mouse CD3 (17A2) (CL488-65077, Clone: 17A2) and 0.5 ug Atlantic Blue™ Anti-Mouse CD223 (AB-65098, Clone: C9B7W), or 0.5 ug Isotype Control. Cells were not fixed.