The data shown is representative of three independent
experiments of similar design. Fosbretabulin manufacturer Using a Luminex multiplex kit, we also measured the levels of a panel of cytokines/chemokines in the BALF collected from each mouse and found that the levels of several neutrophil chemoattractants CXCL1/KC , granulocyte colony stimulating factor or G-CSF , CXCL10/IP-10 , TNF-α , MIP-1α/CCL3 and MIP-1β/CCL4 , CXCL2/MIP-2 , and CCL2/MCP-1  were all present at significantly higher levels in the lungs of galU mutant-infected mice (p < 0.05) at the 24 or 48 h time points (Figure 4B and 4C), correlating well with the peak of neutrophil recruitment at 48 h post-infection. The levels of these same chemokines/cytokines peaked in the lungs of WT FT-infected mice 72-96 hours post-infection (data not shown), corresponding well with the peak of neutrophil recruitment into the lungs on day five post-challenge. It was recently reported that mutations that result in alterations in LPS structure, making the bacterium more likely to be recognized
through TLR4 signaling, could result in robust chemokine expression and early neutrophil recruitment [17, 20]. To determine if the altered kinetics of innate immune responses observed for the galU mutant strain resulted from gross alterations to its LPS structure, we extracted LPS from WT, galU mutant, and wbtA mutant (O-antigen deficient) strains of FT and performed Western blot analysis using a FT LPS-specific mAb. No obvious alteration in LPS laddering was observed, suggesting that mutation of galU did not result in gross changes in synthesis see more of the O-antigen Pevonedistat purchase component of LPS (Figure 5A). We also analyzed the ability of LPS derived from the galU mutant to initiate TLR4-mediated signaling. Using HeLa cells that stably express either TLR2 or TLR4/MD2 that had been transfected with a vector bearing a NFκB-responsive luciferase reporter construct, we determined that neither galU mutant or WT FT lysates were able to stimulate TLR4 while both stimulated TLR2 to the same extent (Figure 5B), suggesting that the lipid A portion of the mutant LPS was not
altered. Figure 5 Mutation of galU does not cause gross changes in O-antigen synthesis, serum sensitivity, Y-27632 2HCl or TLR signaling. Panel A: Bacterial cell lysates (10 μg/lane) and LPS preparations of WT, galU mutant, and wbtA-mutant (O-antigen deficient) FT strains were subjected to SDS-PAGE and Western blotting using an FT LPS-specific monoclonal antibody preparation. Panel B: HeLa-TLR4/MD-2 or HeLa-TLR2 were transiently transfected with a ELAM-luciferase reporter construct, CMV-CD14 and CMV-β-Gal (for normalization) and stimulated for 6 hours with 2μg or 10μg of the indicated FT lysates. NF-κB activation was measured via a luciferase assay. Statistical analyses were performed via one-way ANOVA and significant differences (P < 0.0001) are indicated (***).