title: Outer membrane protein A of Escherichia coli O157:H7 stimulates dendritic cell activation.
abstract: Outer membrane protein A (OmpA) is located in the membrane of Escherichia coli and other gram-negative bacteria and plays a multifunctional role in bacterial physiology and pathogenesis. In enterohemorrhagic E. coli (EHEC), especially serotype O157:H7, OmpA interacts with cultured human intestinal cells and likely acts as an important component to stimulate the immune response during infection. To test this hypothesis, we analyzed the effect of EHEC OmpA on cytokine production by dendritic cells (DCs) and on DC migration across polarized intestinal epithelial cells. OmpA induced murine DCs to secrete interleukin-1 (IL-1), IL-10, and IL-12 in a dose-dependent manner, and this effect was independent of Toll-like receptor 4. Although DCs displayed differential responses to EHEC OmpA and OmpA-specific antibodies enhanced DC cytokine secretion, we cannot discard that other EHEC surface elements were likely to be involved. While OmpA was required for bacterial binding to polarized Caco-2 cells, it was not needed for the induction of cytokine production by Caco-2 cells or for human DC migration across polarized cells.
authors.affiliation: Department of Microbiology and Immunology, 301 University Blvd., University of Texas Medical Branch, Galveston, Texas 77555-1070, USA. altorres@utmb.edu
authors.forename: Alfredo G
authors.initials: AG
authors.lastname: Torres
authors.forename: Yongguo
authors.initials: Y
authors.lastname: Li
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Tutt
authors.forename: Lijun
authors.initials: L
authors.lastname: Xin
authors.forename: Tonyia
authors.initials: T
authors.lastname: Eaves-Pyles
authors.forename: Lynn
authors.initials: L
authors.lastname: Soong
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology*; D018938:Caco-2 Cells; D002465:Cell Movement; D016764:Cell Polarity; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology* / Q000502:physiology; D019453:Escherichia coli O157; D029968:Escherichia coli Proteins / Q000502:physiology*; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL
chemical_list: D001425:Bacterial Outer Membrane Proteins; D016207:Cytokines; D029968:Escherichia coli Proteins; C078167:OMPA outer membrane proteins