Related Experiment Video
Updated: May 8, 2026

Accurate and Simple Measurement of the Pro-inflammatory Cytokine IL-1β using a Whole Blood Stimulation Assay
Published on: March 1, 2011
The 2nd International Standard for Interleukin-2 (IL-2). Report of a collaborative study
Meenu Wadhwa1, Chris Bird, Alan B Heath
1Biotherapeutics Group, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
Abstract:
Two candidate preparations of human sequence recombinant Interleukin-2 (IL-2) were formulated and lyophilized at NIBSC prior to evaluation in a collaborative study for their suitability to serve as a replacement international standard. The preparations were tested by eight laboratories using in vitro bioassays and immunoassays. The candidate preparation 86/500 was judged suitable to serve as a replacement international standard based on the data obtained for activity and stability. On the basis of the results reported here, the preparation coded 86/500 was established by the WHO Expert Committee on Biological Standardisation (ECBS) in 2012 as the WHO 2nd IS for human IL-2 with an assigned value for IL-2 activity of 210IU/ampoule. Calibration of the 2nd IS is primarily based on the bioassay in use in various laboratories and relies exclusively on the estimates calculated relative to the WHO 1st IS for continuity of the IU.

