Recombinant human beta NGF (HZ-1222) stimulates dose-dependent proliferation of the TF-1 human erythroleukemic indicator cell line. Cell number was quantitatively assessed by Prestoblue® Cell Viability Reagent. TF-1 cells were treated with increasing concentration of recombinant beta NGF for 72 hours. The EC50 range is 0.5-3.00 ng/mL.