Measure by its ability to induce proliferation in TF-1 cells.
The ED50 for this effect is <0.5 ng/mL.
The specific activity of recombinant human IL-6 is approximately >5 x 108 IU/mg.
Measure by its ability to induce proliferation in MCF-7 cells.
The ED50 for this effect is <4.4 ng/mL.