Development and validation of a bioassay for interleukin-2.
A reliable and precise method for the determination of IL-2 activity, based on stimulation of CTLL cell proliferation, was developed. Cells were incubated with different concentrations of IL-2 for 24 h in microtiter plates. The stimulatory effect was measured on a plate-reading spectrophotometer by reading the optical density of formazan, which is produced by viable cells from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The bioassay was designed as a four-dose parallel line test, fulfilling pharmacopoeial requirements for assay validity, and the inter-assay relative standard deviation (RSD) for a group of four experiments was 2.6%. The International Standard for human IL-2 and the Reference Reagent for Recombinant DNA-derived IL-2 were employed for potency determinations. The method was found suitable for potency assessments of pharmaceutical formulations of IL-2.
Hammerling
U
U
Pharmacological Division, Medical Products Agency, Uppsala, Sweden.
Henningsson
A C
AC
Sjödin
L
L
D000818:Animals; D002460:Cell Line; D003124:Colorimetry; D007376:Interleukin-2 / Q000032:analysis*; D051379:Mice; D012015:Reference Standards; D015203:Reproducibility of Results
D007376:Interleukin-2