Platelet derived growth factor (PDGF) plays a role in regulating a number of biological processes including cellular proliferation and development. PDGF consists of a disulfide-linked homo- or heterodimer of two chains, A and B, which are encoded by two separate genes. The three possible combinations of the PDGF chains, AA, AB, and BB, are all biologically active. The PDGF receptor (PDGFR) is a protein tyrosine kinase. Ligand binding to the PDGFR leads to tyrosine phosphorylation of numerous intracellular proteins, including the receptor itself. The PDGFR consists of two subunits, α and β, which are encoded by two separate genes. The α subunit binds to both the A and B PDGF chains with high affinity, whereas the β subunit binds only to the B chain with high affinity. Ligand binding results in receptor dimerization, with the PDGF type (AA, AB or BB) influencing the resulting PDGFR subunit composition (αα, αβ, or ββ). That is, PDGF-AA binds to αα receptors, PDGF-AB binds to αα and αβ receptors, and PDGF-BB binds to αα, αβ, and ββ receptors. This antibody reportedly recognizes B chain-containing human PDGF isoforms and does not recognize the PDGF-AA homodimer. Additionally, this antibody reportedly inhibits PDGFR binding of PDGF-AB and -BB, but not PDGF-AA and is thought to recognize a conformational epitope of the PDGF B chain that is dependent on disulfide linkages. This antibody has been reported to inhibit PDGF receptor-binding and mitogenic effects of PDGF-AB and -BB.