title: Surface-layer protein extracts from Lactobacillus helveticus inhibit enterohaemorrhagic Escherichia coli O157:H7 adhesion to epithelial cells.
abstract: Adherence of intestinal pathogens, including Escherichia coli O157:H7, to human intestinal epithelial cells is a key step in pathogenesis. Probiotic bacteria, including Lactobacillus helveticus R0052 inhibit the adhesion of E. coli O157:H7 to epithelial cells, a process which may be related to specific components of the bacterial surface. Surface-layer proteins (Slps) are located in a paracrystalline layer outside the bacterial cell wall and are thought to play a role in tissue adherence. However, the ability of S-layer protein extract derived from probiotic bacteria to block adherence of enteric pathogens has not been investigated. Human epithelial (HEp-2 and T84) cells were treated with S-layer protein extract alone, infected with E. coli O157:H7, or pretreated with S-layer protein extract prior to infection to determine their importance in the inhibition of pathogen adherence. The effects of S-layer protein extracts were characterized by phase-contrast and immunofluorescence microscopy and measurement of the transepithelial electrical resistance of polarized monolayers. Pre-treatment of host epithelial cells with S-layer protein extracts prior to E. coli O157:H7 infection decreased pathogen adherence and attaching-effacing lesions in addition to preserving the barrier function of monolayers. These in vitro studies indicate that a non-viable constituent derived from a probiotic strain may prove effective in interrupting the infectious process of an intestinal pathogen.
authors.affiliation: Research Institute, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
authors.forename: Kathene C
authors.initials: KC
authors.lastname: Johnson-Henry
authors.forename: Karen E
authors.initials: KE
authors.lastname: Hagen
authors.forename: Mahsa
authors.initials: M
authors.lastname: Gordonpour
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Tompkins
authors.forename: Philip M
authors.initials: PM
authors.lastname: Sherman
mesh_terms: D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000494:pharmacology; D002460:Cell Line; D004847:Epithelial Cells / Q000187:drug effects* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000378:metabolism; D052198:Lactobacillus helveticus / Q000737:chemistry*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C490390:SlpB protein, Lactobacillus brevis