Competitive inhibition of adherence of enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli and Clostridium difficile to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027.

AIM: To observe competitive inhibition of adherence of enterotoxigenic Escherichia coli (ETEC), enteropathogenic Escherichia coli (EPEC) and Clostridium difficile (C. difficile) to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027 (B. ado 1027). METHODS: The binding of bacteria to intestinal epithelial cell line Lovo was counted by adhesion assay. The inhibition of adherence of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo by purified adhesin of B. ado 1027 was evaluated quantitatively by flow cytometry. RESULTS: The purified adhesin at the concentration of 10 microg/mL, 20 microg/mL and 30 microg/mL except at 1 microg/mL and 5 microg/mL could inhibit significantly the adhesion of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo. Moreover, we observed that a reduction in bacterial adhesion was occurred with increase in the concentration of adhesin, and MFI (Mean fluorescent intensity) was decreased with increase in the concentration of adhesin. CONCLUSION: The purified adhesin of B. ado 1027 can inhibit the adhesion of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo in a dose-dependent manner.

[Effect of Bifidobacterial adhesin on lipopolysaccharide- and H2O2-induced proliferation and apoptosis of intestinal epithelial cells in vitro].

OBJECTIVE: To study the effect of Bifidobacterial adhesin on proliferation and apoptosis of intestinal epithelial cell induced by lypopolysaccharide (LPS) and H(2)O(2) in vitro. METHODS: With (3)H-TdR incorporation method, flow cytometry and fluorochrome staining, the proliferation and apoptosis of intestinal epithelial cells induced by LPS and H(2)O(2) in vitro were studied. RESULTS: LPS at the dose of 100 microg/L effectively stimulated the proliferation and apoptosis of cells, whereas H(2)O(2) at the dose of 200 micromol/L obviously restrained the proliferative ability while enhanced the apoptosis of the cells. Fluorochrome staining showed cell shrinkage, nuclear condensation and fragmentation under microscope. After treatment with Bifidobacterial adhesin, the cell proliferation and apoptosis decreased significantly in LPS group, and in H(2)O(2) group, cell apoptosis was significantly decreased. CONCLUSIONS: Bifidobacterial adhesin can protect intestinal epithelial cells from the damage by LPS and H(2)O(2), and maintain the balance between the proliferation and apoptosis of the cells.