| Synonyms | Interferon-gamma-inducing factor, IGIF, IL-1g, IL-18, IL1F4, MGC12320, IFN-gamma-inducing factor, Interleukin-1 gamma, IL-1 gamma, Iboctadekin. |
| Introduction | IL-18 is a proinflammatory cytokine. This cytokine can induce the IFN-gamma production of T cells. The combination of this cytokine and IL12 has been shown to inhibit IL4 dependent IgE and IgG1 production, and enhance IgG2a production of B cells. IL-18 binding protein （IL18BP） can specifically interact with this cytokine, and thus negatively regulate its biological activity. |
| Description | Interleukin-18 Rat Recombinant produced in E.Coli is a single, non-glycosylated polypeptide chain containing 158 amino acids and having a molecular mass of 18260 Dalton.
The IL-18 is purified by proprietary chromatographic techniques. |
| Source | Escherichia Coli. |
| Physical Appearance | Sterile Filtered White lyophilized （freeze-dried） powder. |
| Formulation | Lyophilized from a concentrated （1mg/ml） solution in water containing 0.4 x PBS pH=7.2. |
| Solubility | It is recommended to reconstitute the lyophilized Interleukin 18 in sterile 18MΩ-cm H2O not less than 100μg/ml, which can then be further diluted to other aqueous solutions. |
| Stability | Lyophilized Interleukin-18 although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution IL18 should be stored at 4°C between 2-7 days and for future use below -18°C.
For long term storage it is recommended to add a carrier protein （0.1% HSA or BSA）.
Please prevent freeze-thaw cycles. |
| Purity | Greater than 95.0% as determined by（a） Analysis by RP-HPLC.
（b） Analysis by SDS-PAGE. |
| Amino acid sequence | The sequence of the first five N-terminal amino acids was determined and was found to be His-Phe-Gly-Arg-Leu. |
| Biological Activity | The ED50 as determined by the dose-dependant stimulation of IFN-gamma by murine lymph node cells （4 x 105 cells/well） co-stimulated with sub optimal dose of ConA （0.75ug/ml） is 12 ng/ml. The medium was RPMI containing 10% FCS and 50μM 2-ME. |
| Protein content | 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 （InliGenetics）.
2. Analysis by RP-HPLC, using a standard solution of IL-18 as a Reference Standard. |
| Usage | ProSpec's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals. |
