Figures & data
Figure 1. Inhibition of LPS-induced IL-8 production by L. reuteri-conditioned media. HT-29 cells were cultured and stimulated with LPS (25 ng/ml) supplemented with soluble CD14 (solid bars) in the presence of bacterial culture medium (MRS). Pretreatment of HT-29 cells (4 h) with Lactobacillus-conditioned media before LPS challenge significantly diminished the production of IL-8, compared with cells pretreated with MRS media alone (*p<0.05). Human IL-8 levels were measured by quantitative ELISAs (Quantikine, R&D Systems, Minneapolis, MN, USA). MRS, de Man, Rogosa, Sharpe bacteriologic medium.
Figure 2. Strain-dependent suppression of TNF-α in human monocytoid cells by Lactobacillus reuteri. Cell culture bioassays were performed to determine L. reuteri-mediated TNF-α suppression. Human monocytoid cell line, THP-1 (ATCC TIB-202), was co-incubated with Escherichia coli lipopolysaccharide (LPS) and conditioned media derived from four strains of L. reuteri. Secreted human TNF-α cytokine was then measured by TNF-α ELISA in the cell culture supernatants. Human-derived L. reuteri exhibited strain-dependent and cell-contact independent suppression of TNF-α production. L. reuteri strains ATCC PTA 4659 and ATCC PTA 6475 significantly suppressed TNF-α production by 88.7% and 92.4%, respectively, compared with the MRS bacterial medium only control. **Statistical significance with p<0.001. x-axis, bioassay cultures with or without LPS; y-axis, secreted TNF-α in pg/ml; MRS, de Man-Rogosa-Sharpe Lactobacillus-selective bacterial culture medium.
Figure 3. Lactobacillus reuteri inhibits TNF-induced NF-κB activation. KBM-5 cells (2×106 cells/well) were incubated with different L. reuteri conditioned media (20%) for 16 h, activated with TNF (0.1 nM) for 30 min, and analyzed for NF-κB activation by EMSA. The dried gels were visualized with a Storm 820 and radioactive bands were quantified using ImageQuant software (Amersham Pharmacia Biotechnology, Piscataway, NJ, USA). In the presence of TNF-α, pretreatment with L. reuteri ATCC PTA 6475 significantly inhibited NF-κB activation compared with strain ATCC PTA 4659.
