FIG. 2.

LPS-induced oxidative burst was higher in cells expressing TLR4 compared to non-TLR4-expressing controls. The LPS had been purified to ensure that it was a highly specific TLR4 agonist and did not signal in the absence of TLR4. (A) Cells were incubated with H₂DCFDA dye and then treated with various doses of LPS for 15 min. (B) Cells were incubated with H₂DCFDA dye and then treated with 10 μg of LPS per ml for various times. •, TLR4-transfected HEK293 cells; ▴, empty vector-transfected HEK293cells. Data shown are from four separate experiments carried out in duplicate. (C) H₂DCFDA dye oxidation in C57BL/6 and C3H/HeJ bone marrow-derived macrophages treated with 5 μg of LPS per ml for various times. •, C57BL/6; ▴, C3H/HeJ. Data shown are from three independent experiments. All data are expressed as the medians ± the upper and lower quartiles from three independent experiments. *, statistical differences between dye oxidation of LPS-treated and control cells were significant to an overall P value of ≤0.05, as determined with the Wilcoxon test with an adjusted Bonferroni correction.