The international standard for human interleukin-2. Calibration by international collaborative study.

Three lyophilized preparations of interleukin-2 coded 86/500, 86/564 and 86/504 have been evaluated in an international collaborative study for their suitability as an international standard. All of the preparations performed well in the different bioassay systems included in the study, and showed excellent stability on accelerated temperature degradation. Material similar to that in preparation 86/504 has served well as an interim reference reagent for interleukin-2 for 3 years. Therefore with the agreement of the study participants and the authorization of the Expert Committee on Biological Standardization of the World Health Organization, the preparation coded 86/504 was established in 1987 as the 1st international standard for interleukin-2, with a defined potency of 100 IU/ampoule.