title: Expression of B7-1 and B7-2 costimulatory molecules by human gastric epithelial cells: potential role in CD4+ T cell activation during Helicobacter pylori infection.
abstract: Human gastric mucosal epithelial cells display class II MHC, the expression of which is increased during Helicobacter pylori infection. These observations suggest that the gastric epithelium may participate as antigen-presenting cells (APC) during local immune responses. The increase in class II MHC expression occurs in parallel with an elevation in gastric CD4+ T cell numbers within and adjacent to the epithelium. Since the expression of either B7-1 (CD80) or B7-2 (CD86) on APC is required for the activation of T cells, it was important to establish human gastric epithelial cells expressed those surface ligands. The expression of B7-1 and B7-2 was detected on human gastric epithelial cell lines and freshly isolated epithelial cells from gastric biopsies with specific antibodies. B7-2 expression was higher than B7-1 at both protein and transcript levels and was increased after crosslinking class II MHC molecules on IFNgamma-treated epithelial cells and in cells pretreated with the combination of IFNgamma and H. pylori. Similarly, B7-2 expression was higher on gastric epithelial cells from H. pylori-infected tissues compared with those from uninfected specimens. To determine the function of these molecules on gastric epithelial cells, antibodies to B7-1 and B7-2 were shown to reduce the ability of the cells to stimulate alloreactive CD4+ T cells. These observations are the first to demonstrate that B7-1 and B7-2 are expressed on mucosal epithelial cells in situ. Thus, the expression of B7-1 and B7-2 by epithelial cells may allow them to act as APC in regulating local responses such as those that occur during infection with H. pylori.
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston 77555-0366, USA.
authors.forename: G
authors.initials: G
authors.lastname: Ye
authors.forename: C
authors.initials: C
authors.lastname: Barrera
authors.forename: X
authors.initials: X
authors.lastname: Fan
authors.forename: W K
authors.initials: WK
authors.lastname: Gourley
authors.forename: S E
authors.initials: SE
authors.lastname: Crowe
authors.forename: P B
authors.initials: PB
authors.lastname: Ernst
authors.forename: V E
authors.initials: VE
authors.lastname: Reyes
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000502:physiology; D018122:B7-1 Antigen / Q000032:analysis* / Q000502:physiology; D051940:B7-2 Antigen; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D005753:Gastric Mucosa / Q000737:chemistry*; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000502:physiology
chemical_list: D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D000949:Histocompatibility Antigens Class II; D008562:Membrane Glycoproteins