FIG. 4.

Induction of TNF-α (A), IL-6 (B), and KC (C) in mice infected with S. enterica serovar Typhimurium strains at a dose of 2 × 10³ CFU by the i.p. route. Sera from mice infected with the lppA and lppB SKO and lpp DKO mutants were collected at days 1, 3, and 7 postinfection, and the levels of TNF-α, IL-6, KC, and IFN-γ were determined by ELISA and CBA as described in Materials and Methods. The data in panels A and B are data from a typical experiment; three independent experiments were performed. The data in panel C are arithmetic means ± standard deviations based on three independent experiments performed in duplicate. The asterisks indicate statistically significant differences (P ≤ 0.05, as determined by Student's t test) between the groups indicated by the horizontal lines.