TNF alpha

TNF-alpha (Tumor necrosis factor, alpha), a member of the TNF ligand superfamily, is among others, secreted by macrophages, activated monocytes, neutrophils, T-cells, B-cells and natural killer cells stimulated by bacterial lipopolysaccharides. TNF-alpha shows approximately 30% homology with TNF-beta. TNF-alpha plays an important role in the regulation of immune cells. TNF-alpha has many biological activities, including a cytotoxic effect to various tumor cells, causes inflammation, cellular proliferation and plays a critical role in mediating resistance to bacterial infections. Human and murine TNF-alpha show approximately 79% homolgy and human TNF-alpha is active on murine cells with a slightly reduced specific activity

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.

Each batch of ISOkine growth factor is tested for bioactivity and verified to have comparable activity to a commercial source. Bioactivity of ISOkine recombinant human TNF-alpha is assayed by measuring its dose dependent effect in a cytotoxicity assay using Actinomycin-D sensitized L929 cells. The ED50 for this effect is typically < 0.4 ng/ml corresponding to a specific activity > 2.5 x10e6 U/mg. Optimal concentration should be determined for specific applications and cell lines.

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 TNF-alpha is a 19.6 kDa protein containing 158 amino acid residues and contains a 16 a.a. Histidine-based tag for a total length of 174 a.a. The recombinant protein migrates an apparent molecular mass of 24 kDa in SDS-PAGE.