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 (IntelliGenetics).

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.

Size :
25ug