Chemotaxis of monocytes and neutrophils to platelet-derived growth factor

Abstract

The platelet-derived growth factor (PDGF) is shown to be chemotactic for monocytes and neutrophils. Maximum monocyte chemotaxis to PDGF is fully equal to that achieved with C5a and occurs at ≃20 ng/ml (≃0.7 nM). Maximum neutrophil chemotaxis is ≃60% that achieved with C5a but occurs at ≃1 ng/ml (≃32 pM). The chemotactic activity of PDGF is blocked by specific antisera to PDGF and by protamine sulfate, a competitive inhibitor of PDGF binding to cell surfaces. In contrast to PDGF, epidermal growth factor shows no chemotactic activity for inflammatory cells at 0.5-100 ng/ml. The high level of chemotactic activity of PDGF suggests that in addition to its role as a mitogen for smooth muscle cells and fibroblasts, PDGF may be involved in attracting inflammatory cells to sites of platelet release.