Figure 6.

Comparison between activation potential by lysates of various Salmonella enterica serovars (A) and Campylobacter jejuni (B) strains on TLR5 chimera-expressing NF-ĸB reporter cells. HEK-Blue Null1 NF-κB reporter cells were transiently transfected with appropriate amounts of expression plasmids coding for human TLR5-V5 or for chimeric receptors (empty vector pEF6-V5: 100 ng, human (h): 50 ng, chicken/human (ch/h): 50 ng, mouse/human (m/h): 50 ng, porcine/human (p/h): 100 ng, bovine/human (b/h): 100 ng). The different TLR5 chimeric constructs are color-coded as indicated below the x-axis and in the graph. After 24 hours, transfected cells were coincubated with Salmonella enterica or C. jejuni lysates (100 ng total protein content per well) for 11 h; NF-κB-dependent SEAP production was determined by colorimetric measurements at 620 nm (see Methods). Values are depicted as relative values (in percent) to each corresponding construct activated by 20 ng of recombinant FliC as reference, which was set to 100%. Empty vector-transfected cells activated by lysate were defined as background and subtracted for each strain separately. This evaluation does not allow a direct comparison between chimeras, but allows the direct comparison between different bacterial strains/serovars for each chimeric receptor, and of relative host activation patterns between strains. Activation by single strains of each serovar is separately highlighted by alternating white or grey background shading. Additionally, strain groups are subdivided according to their serovar or sequence type (ST, for C. jejuni isolates) by dashed lines; each serovar or strain group (ST) and the group-specific strain names (according to Table S1) are indicated above the bars and color-coded in the same color. Mean and standard deviation from biological triplicates of a representative experiment (out of two independent experiments) are shown. For C. jejuni, results for strain 11168 are given as a reference.