Measure by its ability to induce proliferation in CTLL-2 cells.
The ED50 for this effect is <0.2 ng/mL.
The specific activity of recombinant human IL-2 is approximately >2.5 x 107 IU/mg.
Measure by its ability to induce proliferation in NK cells.
The ED50 for this effect is <46 ng/mL.