Anti-inflammatory effects of bifidobacteria by inhibition of LPS-induced NF-κB activation

Figure 1 Quantification of NF-κB-driven SEAP activity in the supernatants of HT-29 clone 34 cells challenged with different bacterial strains at moi = 100 for 16 h. Results are shown as RLU and are mean ± standard deviation (SD) of triplicate measurements of one representative of three independent experiments. neg: negative control, no bacteria.

Figure 2 Dose- and strain-dependent inhibition of LPS-induced NF-κB activation by different bifidobacteria. SEAP activity was quantified in the supernatants of HT-29 clone 34 cells pre-incubated with different bifidobacteria at moi = 10 (dark grey bars) or moi = 100 (light grey bars) and subsequently stimulated with LPS + HM for 16 h. Cells treated with medium only served as negative control (neg; white bar) and positive controls (pos; black bar) were cells challenged with LPS + HM without bacterial pre-treatment. Results are means ± standard error of the mean (SEM) of three independent experiments performed in triplicate. RLU of indicidual experiments were normalised to give 100 RLU for the positive control.

Figure 3 Microscopic examination of cellular viability. Trypan blue exclusion was monitored in HT-29 clone 34 cells challenged with LPS + HM for 16 after pre-incubation with bifidobacteria (B. longum NCC2705 or B. bifidum S17; moi = 100). Positive control (pos) was cells incubated with LPS + HM without bacterial pre-treatment. As a control for trypan blue staining cells were incubated for 16 h in cell culture medium at pH 4 (dead).

Figure 4 NF-κB-driven SEAP activity in the supernatants of HT-29 clone 34 cells pre-incubated with different bifidobacteria and subsequent stimulation with TNF-α (10 μg/L) for 16 h in the presence of 50 mL/L HM. Cells treated with medium only served as negative control (neg) and positive controls (pos) were cells challenged with TNF-α + HM without bacterial pre-treatment. Results are given as RLU and are means ± SD of triplicate measurements of a representative of two independent experiments.