IFN gamma

IFN-gamma, a type II interferon and an acid-labile interferon, is mainly produced by CD4 and CD8 T-lymphocytes and natural killer cells activated by antigens, mitogens or alloantigen’s. IFN-gamma shows no significant homology with IFN-beta or IFN-alpha. IFN-gamma has antiviral and antiparasitic activities and exhibits also immunoregulatory and proinflammatory activities. IFN-gamma induces cytokine production and promotes antigen presentation by up regulating the expression of MHC proteins as well as other antigen proteins. In contrast to other interferons, which are mostly antiviral, the main activity of IFN-gamma seems to be immunomodulatory. Human IFN-gamma is species-specific and is only biologically active in human and primate.

Produced in the endosperm tissue of barley grain (Hordeum vulgare).

PBS pH 7.2, sterile filtered through 0.2 µm filter.

Greater than 95% by SDS-PAGE gel analysis.

Note: Always centrifuge the vial before opening. It is recommended to reconstitute the lyophilized protein in sterile buffered saline to a concentration of no less than 100 µg/ml. For long term storage of the reconstituted solution it is recommended to add a carrier protein (0.1% HSA or BSA).

The lyophilized protein, though stable at room temperature for few weeks, is best stored at -20°C. Reconstituted protein should be used immediately or stored in working aliquots at -20°C. Avoid repeated freeze-thaw cycles.

The bioactivity of ISOkine® recombinant human IFN-gamma was determined by its dose dependent cytostatic effect, in the presence of TNF-alpha, on HT-29 (human carcinoma) cells.

The ED50 for this effect is <0.4 ng/ml corresponding to specific activity of > 2.5 x 10e6 U/mg.

We recommend that the optimal concentration for each specific application be determined by an initial dose-response assay. Each batch of ISOkine® growth factor is tested for bioactivity and verified to have comparable activity to a commercial source.

Endotoxin level is less than 0.005ng per µg of ISOkine® product (0.05EU/µg).

Purified ISOkine® product carries no pyrogenic or pro-inflammatory contaminants, as assayed with monocyte activation test using Human 10-plex Cytokine Assay measuring IL-6, TNF-alpha and IL-1 beta induction. ** Ref. The Blood Bank, University Hospital of Iceland, Reykjavik, Iceland

Recombinant human IFN gamma contains 143 amino acids and a 16 a.a. Histidine-based tag for a total length of159 a.a. and has a predicted molecular mass of 18.8 kDa. As of glycosylation, the recombinant protein migrates with an apparent molecular mass of 20-25 kDa in SDS-PAGE.