Tumor necrosis factor alpha (TNF-alpha), also known as cachectin and TNFSF1A, is the prototypic ligand of the TNF superfamily. It is a pleiotropic molecule that plays a central role in inflammation, apoptosis, and immune system development.
Specifications and Use for R&D TNF-alpha
Source of R&D TNF
• A DNA sequence encoding the mature human TNF-α protein sequence (Accession # X01394) was expressed in E. coli.
Molecular Mass of R&D TNF
• The purified recombinant human TNF-α has a molecular mass of approximately 17.5 kDa. The recombinant protein preparation is a mixture of a 158 amino acid residue form containing an N-terminal methionine and a 157 amino acid residue form with the authentic sequence of mature human TNF-α.
Purity of R&D TNF
• > 97%, as determined by SDS-PAGE and visualized by silver stain.
• < 1.0 EU per 1 μg of the cytokine as determined by the LAL method.
Activity of R&D TNF-alpha
• Measured in a cytotoxicity assay using the TNF susceptible murine L-929 cell line in the presence of the metabolic inhibitor actinomycin D (Matthews, N. and M.L. Neale in Lymphokines and Interferons, a Practical Approach, 1987, M.J. Clemens, A.G. Morris and A.J.H. Gearing, eds., IRL Press, p. 221).
♦ The ED50 for this effect is typically 25 - 100 pg/mL in a fluorometric assay using the redox senstitive dye, Resazurin (R&D Systems, Catalog # AR002).
Formulation of R&D TNF
• Lyophilized from a 0.2 μm filtered solution in PBS containing 50 μg of bovine serum albumin per 1 μg of cytokine.
• It is recommended that sterile phosphate-buffered saline containing at least 0.1% human serum albumin or bovine serum albumin be added to the vial to prepare a stock solution of 100 μg/mL of the cytokine.
Reconstitution of R&D TNF
• Lyophilized samples are stable for up to twelve months at -20° C to -70° C.
Storage of R&D TNF-alpha
• Upon reconstitution, this cytokine can be stored under sterile conditions at 2° - 8° C for one month or at -20° C to -70° C in a manual defrost freezer for three months without detectable loss of activity.
• Avoid repeated freeze-thaw cycles.