TGF- β1 (transforming growth factor beta 1) is one of three closely related mammalian members of the large TGF-β superfamily that share a characteristic cystine knot structure.1 - 7 TGF-β1, -2 and -3 are highly pleiotropic cytokines that are proposed to act as cellular switches that regulate processes such as immune function, proliferation and epithelial-mesenchymal transition.

Specifications and Use for R&D TGF-beta1

Source
• Purified from human platelets. The human platelets used for the isolation of this product were certified by the supplier to be HIV-1 and HBsAg negative at the time of shipment. Human blood products should always be treated in accordance with universal handling precautions.

Molecular Mass
• The mature disulfide-linked homodimeric human TGF-β1 contains two 112 amino acid residue peptides and has a predicted molecular mass of approximately 25 kDa.

Purity
• > 97%, as determined by SDS-PAGE and visualized by silver stain.

Endotoxin Level
• < 1.0 EU per 1 μg of the cytokine as determined by the LAL method.

Activity
• Measured by its ability to inhibit the IL-4-dependent proliferation of mouse HT-2 cells. Resazurin (R&D Systems, Catalog # AR002) dye was used in the assay as a fluorescence indicator for cell proliferation (Tsang, M. et al., 1995, Cytokine 7:389).
• The ED50 for this effect is typically 0.04 - 0.2 ng/mL.

Formulation
• Lyophilized from a 0.2 μm filtered solution in 35% acetonitrile and 0.1% TFA, containing 50 μg of bovine serum albumin per 1 μg of cytokine.

Reconstitution
• It is recommended that sterile 4 mM HCl containing at least 0.1% human serum albumin or bovine serum albumin be added to the vial to prepare a stock solution of no less than 10 μg/mL. 

Storage
• Lyophilized samples are stable for up to twelve months from date of receipt at -20° C to -70° C.
• 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.