Figure 2. Flagellin expression attenuates S. typhimurium in vivo.

(a) WT or Nlrc4^−/−mice were infected with 100 colony forming units (CFU) ST-WT or ST-FliC^ON and survival was monitored. (b) WT mice were infected with equal numbers of two bacterial strains marked with different antibiotic markers as indicated. CFU in the spleen were determined after 48h and the log of the ratio is shown as the competitive index. Note that a competitive index of -2 corresponds to a 100-fold reduction in the ampicillin resistant strain. (c) Competitive index of ST-FliC^ON/ST-WT in various tissues. (d–j) Competitive index of ST-FliC^ON/ST-WT in the indicated WT or knock out mice at 48 h post infection. Samples marked with * are statistically significant from the other samples in the same graph (p < 0.05); ns: not significantly different from WT or other samples marked with “ns” (p > 0.05). (k, l) WT, Casp1^−/−, or Il1b^−/−Il18^−/−mice were infected intraperitoneally with (k) L. pneumophila (data shown from n=4, 6, and 6 mice, respectively, representative of two experiments) or (l) B. thailandensis (data shown from n=6, 4, and 6 mice, respectively, representative of four experiments). CFU were enumerated 24 h later from the draining lymph nodes. * = p < 0.05, NS = p > 0.05. See Supplementary Table 1 for mouse numbers in panels b–j.