Human peripheral blood monocytes secrete a unique form of PDGF.

ABSTRACT

PDGF isolated from platelets and forms of PDGF produced by cells transformed with the v-sis gene (PDGF B chain) or U-20S osteosarcoma cells which express the PDGF A chain gene are known to be processed as disulfide-linked dimers of approximately 30 kd. Western blot analysis with anti human PDGF antibody of the PDGF-like factor synthesized and secreted by human blood monocytes (MDGF) on SDS gels indicates that it lacks interchain disulfide bridges and behaves as a 16-kd monomer under nonreducing conditions. Additionally, MDGF exhibits different sensitivities to either formic acid or CNBr cleavage compared to PDGF A or B chain molecules indicating it may have a different primary structure. These data suggest that MDGF represents a unique form of PDGF which lacks interchain disulfide bridges and may represent a new member of the PDGF family of growth factors.