For immunoblotting, anti-FLAG M2 antibody (Sigma), the anti-PSG monoclonal antibody BAP1 (Genovac), and the anti-human Fc antibody (KPL) were employed. Neutralization of TGFB1 was performed by adding 10 lg/ml of the anti-human TGFB1 neutralizing antibody (R&D Systems) to the cells 10 min before PSG1 addition. Normal chicken Ig antibody, also obtained from R&D Systems, was used as the control. Recombinant human VEGFA was obtained from Immunotools.