PlGF activates normal mononuclear cells, increasing production of inflammatory cytokine IL-1β, chemokines MCP-1 and IL-8, and the angiogenic growth factor VEGF. (A) Ribonuclease protection assay performed using RNA from normal peripheral blood MNCs from 4 subjects exposed to exogenous PlGF (250 ng/mL) for 1 hour (lanes 5-8) or left untreated (lanes 1-4). HeLa cell RNA was used as a control RNA (lane 9). (B) Densitometry analyses were performed on appropriate exposures on the different bands and normalized for loading.