We have previously reported that recombinant GST-PSG1 purified from insect cells induces TGFB1 in human monocytes and in murine macrophages [9] . Human monocytes secreted PSG1 AND ANGIOGENESIS 29 TGFB1 in response to PSG1-Fc treatment, starting at a concentration of 10 lg/ml and up to the highest concentration tested (50 lg/ml) compared to FLAG-Fc-treated cells ( Fig.  2A) . We also observed a significant induction of TGFB1 in human monocytes (between two-and threefold the amount of TGFB1 secreted over the control protein-treated cells, depending on the donor) at a PSG1-FLAG concentration of 10 lg/ml.