Measure by its ability to inhibit the IL-4 dependent proliferation in HT-2 cells.
The ED50 for this effect is <0.1 ng/mL.
The specific activity of recombinant human TGF beta 1 is approximately >5 x 107 IU/mg.
Measure by its ability to induce proliferation in MCF-7 cells.
The ED50 for this effect is <3.2 ng/mL.