title: Peritoneal cavity B-1a cells promote peripheral CD4+ T-cell activation.
abstract: Innate-like murine B-1a cells are well known for their ability to secrete natural IgM. Their non-Ab mediated functions, including Ag presentation to CD4(+) T cells, are less well explored. Using combined adoptive transfer experiments with peptide-pulsed peritoneal cavity (PerC)-derived B-1a cells and CFSE-labeled T cells, we show that B-1a cells present Ag to CD4(+) T cells from the periphery in vivo. In vitro characterization, using co-cultures in which B-1a or splenic B cells presented whole OVA protein to OVA-specific Tg T cells, shows that B-1a cells differentially promote intracellular cytokine-expressing T cells. PerC-derived B-1a cells increase the percentage of IL-10-producing T cells along with IL-4- and IFN-γ-producing CD4(+) T cells. These data suggest that B cells in the PerC have the potential to influence peripheral immune responses without the necessity to migrate out of this location. This, to our knowledge previously undescribed, immuno-logical pathway potentially plays a role in the presentation of gut microbiota-derived Ags to peripheral T cells.
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Bram
authors.initials: B
authors.lastname: Margry
authors.forename: Willemien H
authors.initials: WH
authors.lastname: Wieland
authors.forename: Peter J
authors.initials: PJ
authors.lastname: van Kooten
authors.forename: Willem
authors.initials: W
authors.lastname: van Eden
authors.forename: Femke
authors.initials: F
authors.lastname: Broere
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology; D010529:Peritoneal Cavity / Q000166:cytology*
chemical_list: D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin
keywords: Antigen presenting cell (APC); B-1 cell; B-1a cell; IL-10; Peritoneal cavity