Fig. 5

Immune response and functional effect of crosslinked flagella in Caco-2 cells. a Portions of extracted flagella were centrifuged though 100kdA filters to separate retentate filaments from filtrate monomers and, in addition to the original unfiltered extracts, 120 ng of each was added to Caco-2 epithelial monolayers harboring a NF-κB luciferase reporter vector. After 6 h, firefly and renilla luciferase were measured to assess the induction of NF-κB. Results include data from three independent experiments with standard error shown. Asterisk, hash, and psi symbols indicate statistically-significance difference comparing the unfiltered, filtrate, and retentate treatments, respectively, to ΔFliC. b Adherence and invasion assay performed with S. Typhimurium SPN313 cells harboring the empty vector (ΔFliC) or encoding the FliC derivatives were added to the apical side of Caco-2 cells. Invasion and adherence were assessed after 2 h and compared to the initial inoculum. Data from two independent experiments with standard deviation shown. Asterisk symbol indicates statistically-significance difference compared to ΔFliC. Single symbol; p < 0.05, double symbol; p < 0.01 as determined by 2-way ANOVA with Tukey’s multiple comparisons test