Fig. 1.

Type I interferon (IFN) increases chemokine concentration in the culture supernatant of human pulmonary arterial endothelial cells (HPAEC). HPAEC were stimulated with IFN-α or IFN-β at the indicated concentrations. Protein levels of (a) CX3CL1 (fractalkine), (b) CCL5 [regulated upon activation normal T cell expressed and secreted (RANTES)] or (c) CCL2 (MCP-1) in the culture supernatant of HPAEC at 72 h. Data from three independent experiments are presented as mean ± standard error. **P < 0·01; ***P < 0·001 in comparison with non-stimulated controls.