Figure 8.

Deletion of fliC in pathogenic and nonpathogenic Bp strains abolishes TLR5 activation by the live microorganisms. (A) Wild-type Bp K96243 and fliC mutant DDI3319 on motility agar after 24 h. (B) Loss of the ability to activate TLR5 by the fliC mutant. Mutation in fliC does not affect activation of TLR2 by the fliC mutant. Significant differences in TLR5 activation by wild-type Bp K9624 and flicC mutant DDI3319 is shown above the activity. (C) Nonpathogenic B. thailandensis E264 activates primarily TLR2 similar to BpK. (D) Anti-TLR5 antibody significantly inhibits TLR5 activation by live B. thailandensis E264. (E) Mutation of fliC in B. thailandensis E264 (DDI3196) abrogates motility, but it can be partially restored (DDI3196+pMo168+fliC). (F) Filtration of B. thailandensis E264 abrogates TLR5 activation (panel 1). Filtration of cells and deletion of fliC in B. thailandensis E264 both abolishes TLR5 activation (panel 2). In the partially recombinant DDI3196+pMo168+fliC TLR5 activation is elevated, and TLR5 activity can be detected in the cell-free filtrate (panel 3). The media control was PBS, and positive controls (Pos Con) were St FliC (2 ng) for TLR5 and HKLM (2 x 10⁶ cells) for TLR2. The activation of TLRs was analyzed in triplicate and results represent one of two independent studies. Results of TLR activation are presented as geometric mean with standard error of the mean. Significant differences between samples are shown above the results. Significant values compared to media control are shown: *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; *****P ≤ 0.00001.