The Mouse Cytokine Positive Control Cells are recommended for use as positive control cells when establishing an intracellular cytokine staining protocol. Mouse splenocytes were stimulated with ConA (3 µg/mL) for two days, followed by recombinant IL-2 (20 ng/mL) and IL-4 (20 ng/mL) for three days. The cells were then restimulated with immobilized anti-mouse CD3 (10 µg/mL) and soluble anti-mouse CD28 (2 µg/mL) in the presence of Brefeldin A for 5 hours. These cells contain subpopulations that express IL-2, IL-3, IL-4, IL-10, GM-CSF, and IFN gamma. The cells have been fixed with formaldehyde and are provided in a stabilizing buffer so that they may be stored at -80°C for up to six months or at 2-8°C for up to one month.