title: Interferon-gamma and B-cell Activating Factor (BAFF) promote bovine B cell activation independent of TLR9 and T-cell signaling.
abstract: We previously reported that CD21(+) B cells purified from bovine blood do not respond to CpG-ODN stimulation unless either CD14(+) monocytes or B-cell Activating Factor (BAFF), a cytokine produced by activated monocytes, are present. In this report, we present evidence that CD14(+) monocytes are critical for CpG-specific lymphocyte proliferation within the peripheral blood mononuclear cell (PBMC) population but that this response is not mediated by soluble factors produced by CpG-activated monocytes. We further determine that bovine monocytes stimulated with IFN-γ induce expression of the BAFF gene and that recombinant IFN-γ and BAFF induced robust B cell activation when cultured in the absence of CpG ODN. These data suggest that CpG-stimulated monocytes may indirectly promote B cell activation by promoting release of cytokines and/or other soluble factors from accessory cells which in turn act on CpG-stimulated B cells to promote antigen-independent and T cell independent B cell activation. Understanding the T cell independent signals that induce B cell activation has important implications for understanding B cell development in locations where T cells are limited and in understanding polyclonal B cell activation that may contribute to autoimmune diseases.
authors.affiliation: Vaccine and Infectious Disease Organization - International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N.
authors.forename: Rachelle
authors.initials: R
authors.lastname: Buchanan
authors.forename: Yurij
authors.initials: Y
authors.lastname: Popowych
authors.forename: Crystal
authors.initials: C
authors.lastname: Dagenais
authors.forename: Natasa
authors.initials: N
authors.lastname: Arsic
authors.forename: George K
authors.initials: GK
authors.lastname: Mutwiri
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Potter
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Babiuk
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Griebel
authors.forename: Heather L
authors.initials: HL
authors.lastname: Wilson
mesh_terms: D000818:Animals; D053264:B-Cell Activating Factor / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000187:drug effects*; D002417:Cattle / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000276:immunology / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*; D051217:Toll-Like Receptor 9 / Q000276:immunology / Q000502:physiology*
chemical_list: D053264:B-Cell Activating Factor; C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D051217:Toll-Like Receptor 9; D007371:Interferon-gamma