抄録
The platelet derived growth factor (PDGF) is a powerful mitogen for cells of mesenchymal origin and a potent chemoattractrant for human neutrophils and for human monocytes. PDGF also activates neutrophils to aggregate, to adhere, to generate superoxide, and to release neutrophil specific ganule contents. The binding of human 125I-PDGF to these cells was examined. Binding to neutrophils was nearly complete at 5min and to monocytes was complete at 30min. The Kd of 125I-PDGF was 2nM for neutrophils and for monocytes; ∼2, 000 sites/neutrophil and/monocyte were found. Neither EGF nor FMLP were competitive with 125I-PDGF for neutrophil binding. Unlabelled PDGF was fully competitive with 125I-PDGF. Pre-incubation of PF4 and LA-PF4 at 10μg/ml blocks 125I-PDGF binding to neutrophils. The Kd of 125I-PDGF binding to neutrophils and monocytes correlates well with the optimal concentrations of PDGF for neutrophil and monocyte activation. These results suggest that PDGF interacts with specific high affinity receptor on the cell surface of neutrophils and monocytes, and that the receptor function might be regulated by PF4 and LA-PF4.
