IFNβ rescues IL-10–suppressed IP-10 mRNA expression. TG-elicited macrophages (1 × 10⁷ cells/sample) were treated with LPS (10 ng/mL), IFNβ (500 U/mL), or IL-10 (25 ng/mL) as indicated for 4 hours before measurement of IP-10 and GAPDH mRNA levels using northern hybridization and phosphorimage analysis as described in the legend to Fig 2. Similar results were obtained in two separate experiments.