Quantification of CXCL-10 and IL-8 in culture supernatant of U937 cells by ELISA. U937 cells were pretreated with or without 3 mg/ml PGSE for 24 hours prior to 20 units/ml TNF-α stimulation for 16 hours. After treatment, the level of CXCL-10 in culture supernatants was measured by specific ELISA kit according to the supplier's procedures. Values represent the average ± SD of three independent experiments and statistically analyzed by two tailed, paired t-test. *: p < 0.05. PGSE, 70% ethanol-water extracts of ginseng; CXCL-10, interferon gamma-inducible protein-10; IL-8, interleukin-8.