Platelet-derived growth factor promotes human peripheral monocyte activation

Abstract

Like in the polymorphonuclear leukocyte (PMN), the platelet-derived growth factor (PDGF) purified to homogeneity is capable of inducing monocyte activation responses as evaluated by generation of superoxide anion (O2·-) from membrane-associated oxidase system, release of granule enzymes, and enhanced cell adherence and cell aggregation. Superoxide anion release was maximized at 10 ng/mL PDGF and was comparable to that induced by 10-7 mol/L formyl-methionyl-leucyl-phenylalanine. The potency of PDGF to induce this response in monocytes was of the same magnitude as that observed in PMNs. Similarly, lysozyme release and monocyte adherence were also increased in a dose-dependent manner and achieved maximal responses at 40 ng/mL concentration of PDGF. The PDGF concentration required to achieve maximal monocyte aggregation was two-fold (60 ng/mL) of that found for PMNs. In contrast to PMNs, a positve correlation (γ = .93; P < .01) was observed between the increases of PDGF concentration and β-glucuronidase release. These findings indicate that PDGF can induce the full sequence of cell activation events in human monocytes similar to human PMNs.