Biological or Clinical Significance:
Transforming growth factor (TGF), a ‘factor’ that promoted the transformation of cultured fibroblasts into a tumor-like phenotype, was subsequently found to be more of a tumor suppressor than tumor promoter and to be a mixture of two proteins, TGF-α and TGF-β. These molecules are members of a superfamily that includes TGF-β 1 through 5, bone morphogenic proteins, activins and inhibins. Human TGF-β 1 is a 25 kDa, disulfide-linked, non-glycosylated homodimer.
TGF-β 1 is cleaved from the C-terminus of a disulfide-linked dimer of pro-TGF-β 1 by a subtilisin-like pro-protein convertase protease. It is normally secreted as an inactive, or latent, complex.
Two different receptor proteins are involved in TGF-β 1 signaling.TGF-β 1 is synthesized, with only a few exceptions, by virtually all cells, and TGF receptors are expressed by all cells.
There are three fundamental activities: TGF-β 1 modulates cell proliferation, generally as a suppressor; TGF-β1 enhances the deposition of extracellular matrix through promotion of synthesis and inhibition of degradation; TGF-β 1 is immunosuppressive through a variety of mechanisms. The specific action of TGF-β on a particular cell depends on the exact circumstances of that cell’s environment.
Principle of Test Method:
The TGF-B1 assay is a solid-phase ELISA that employs the quantitative sandwich enzyme immunoassay principle.