Platelet-Derived Growth Factor (PDGF) is the major serum mitogen for cells of mesenchymal origin in humans. The biologically active protein is a dimer composed of two related polypeptides designated A and B. The PDGF protein has been implicated both directly as well as indirectly in several pathological states including neoplasia, arthritis, arteriosclerosis and bone marrow sclerosis. This antibody is specific for B form and reacts with PDGF(AB) and PDGF(BB) protein.