Figure 3.

Sphingosine or compound 5 enhances IL‐1β release in the presence of LPS in a non‐additive manner. Differentiated U937 cells were treated with LPS (1 μg·mL⁻¹) for 2 h and then with sphingosine (Sph; 20 μM) or compound 5 (Cpd5; 10 μM) or both sphingosine and compound 5 for 1 h and the supernatants assayed for IL‐1β by elisa. Results are expressed as means ± SEM for six independent experiments. *P < 0.05, significantly different from LPS alone; † not significantly different from LPS/Sph or LPS/compound 5; one‐way ANOVA with Bonferroni post test.