Platelet derived growth factor is present in human placenta: purification from an industrially processed fraction

Platelet derived growth factor was purified from an industrially processed fraction of human placenta (EAP) donated by the Institut Merieux. We first demonstrated that EAP contains PDGF and the quantity of this growth factor was estimated by inhibition of its biological activity using antibodies against PDGF. According to this first estimation, 1 l of EAP (obtained from 125 kg of placenta) contains 10-1000 micrograms of PDGF. A purification procedure including fast flow chromatography (cationic S), heparin Sepharose affinity, chromatography on Cibacron Blue followed by a reverse phase on a C8 column gave a 6000-fold enrichment with a yield of 14%. This result suggests that the PDGF content in 1 l of EAP is between 10 and 30 micrograms. Mitogenic activity was measured on human fibroblast AG1523, Chinese hamster fibroblasts CCL39 and bovine epithelial cells BEC. Dose-response curves indicate that our preparation of purified PDGF from human placenta induces 50% of the maximal tritiated thymidine incorporation in CCL39 at a dose of 5 ng of PDGF/ml of culture medium.