The sequence of the first five N-terminal amino acids was determined and was found to be His-Phe-Gly-Arg-Leu.
The ED50 as determined by the dose-dependant stimulation of IFN-gamma by murine lymph node cells (400,000cells/well) co-stimulated with sub optimal dose of ConA (0.75ug/ml) is 12ng/ml corresponding to a specific activity of 84,000U/mg. The medium was RPMI containing 10% FCS and 50uM 2-ME.
Lyophilized from a concentrated (1mg/ml) solution in water containing 0.4 x PBS pH=7.2.
Sterile Filtered White lyophilized (freeze-dried) powder.
Protein quantitation was carried out by two independent methods
1. UV spectroscopy at 280 nm using the absorbency value of 0.213 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).
2. Analysis by RP-HPLC, using a standard solution of IL-18 as a Reference Standard.
Greater than 95.0% as determined by(a) Analysis by RP-HPLC.
(b) Analysis by SDS-PAGE.
It is recommended to reconstitute the lyophilized Interleukin 18 in sterile 18MΩ-cm H2O not less than 100ug/ml, which can then be further diluted to other aqueous solutions.
Lyophilized Interleukin-18 although stable at room temperature for 3 weeks, should be stored desiccated below -18oC. Upon reconstitution IL18 should be stored at 4oC between 2-7 days and for future use below -18oC.
For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA).
Please avoid multiple freeze-thaw cycles.
Interferon-gamma-inducing factor, IGIF, IL-1g, IL-18, IL1F4, MGC12320, IFN-gamma-inducing factor, Interleukin-1 gamma, IL-1 gamma, Iboctadekin.
