title: B cells exposed to enterobacterial components suppress development of experimental colitis.
abstract: BACKGROUND
  B cells positively contribute to immunity by antigen presentation to CD4(+) T cells, cytokine production, and differentiation into antibody secreting plasma cells. Accumulating evidence implies that B cells also possess immunoregulatory functions closely linked to their capability of IL-10 secretion.
  
  
  METHODS
  Colitis development was followed in CD4(+) CD25(-) T cell transplanted SCID mice co-transferred with B cells exposed to an enterobacterial extract (ebx-B cells). B and T cell cytokine expression was measured by flow cytometry and enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  We demonstrate that splenic B cells exposed to ebx produce large amounts of IL-10 in vitro and express CD1d and CD5 previously known to be associated with regulatory B cells. In SCID mice transplanted with colitogenic CD4(+) CD25(-) T cells, co-transfer of ebx-B cells significantly suppressed development of colitis. Suppression was dependent on B cell-derived IL-10, as co-transfer of IL-10 knockout ebx-B cells failed to suppress colitis. Ebx-B cell-mediated suppression of colitis was associated with a decrease in interferon gamma (IFN-γ)-producing T(H) 1 cells and increased frequencies of Foxp3-expressing T cells.
  
  
  CONCLUSIONS
  These data demonstrate that splenic B cells exposed to enterobacterial components acquire immunosuppressive functions by which they can suppress development of experimental T cell-mediated colitis in an IL-10-dependent way.
authors: Department of International Health, Immunology and Microbiology, Panum Institute, University of Copenhagen, Denmark. Esbens@sund.ku.dk
authors: Esben Gjerløff Wedebye
authors: EG
authors: Schmidt
authors: Hjalte List
authors: HL
authors: Larsen
authors: Nanna Ny
authors: NN
authors: Kristensen
authors: Steen Seier
authors: SS
authors: Poulsen
authors: Mogens Helweg
authors: MH
authors: Claesson
authors: Anders Elm
authors: AE
authors: Pedersen