Lyophilized pegylated mouse IL22 although stable at room temperature for several days, should be stored desiccated below -20 degree C. Upon reconstitution at > 0.1 pegylated mIL22 mg/ml and up to 2 mg/ml and filter sterilization it can be stored at 4 degree C or even room temperature for several weeks making it suitable for long term infusion studies using osmotic pumps. At lower concentration addition of a carrier protein (0.1% HSA or BSA) is suggested. Please prevent freeze-thaw cycles.