FIG. 1.

Time course of plasma cytokines after the combined administration of LPS (L) and flagellin (F). Conscious mice received an i.v. injection of S. enterica serovar Enteritidis LPS (20 μg) or recombinant S. enterica serovar Muenchen flagellin (20 μg), or a combination of both toxins (each at 10 μg). Plasma was obtained after 1 and 4 h for the determination of the circulating levels of TNF-α (A) and IL-6 (B). A significant synergy between LPS and flagellin was noted for TNF-α (at 1 h) and IL-6 (at 4 h). n = 5 to 6 mice/group. Means ± standard errors: *, P < 0.05 for LPS plus flagellin versus either LPS or flagellin alone.