title: Split peripheral tolerance: CD40 ligation blocks tolerance induction for CD8 T cells but not for CD4 T cells in response to intestinal antigens.
abstract: The role of antigen-presenting cells in the balance between immunity and tolerance to intestinal antigens remains poorly understood. In this study, we examined whether CD40 ligation affects the induction of CD4 and CD8 T cell tolerance in response to intestinal antigens. We show that an agonistic anti-CD40 mAb treatment did not block the induction of OVA-specific CD4 T cell tolerance, whereas this approach enabled strong priming of OVA-specific cytotoxic T cells (CTL), preventing CTL tolerance to intestinal antigen. Such CTL priming was independent of CD4 T cell help but required B7 costimulation. Co-administration of anti-CD40 mAb increased the synthesis of IL-2 and the expression of CD25 by CD8 T cells, but neither IL-2 production nor CD25 expression by CD4 T cells was enhanced by anti-CD40 mAb. However, neutralization of TGF-beta together with addition of agonistic anti-CD40 mAb was able to reverse CD4 T cell tolerance. These findings suggest that the induction of tolerance versus immunity against intestinal antigens is determined by the status of the antigen-presenting cells and that signals via CD40 differently regulate the outcome of CD4 and CD8 T cells in vivo.
authors.affiliation: Laboratory of Immunology, Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea.
authors.forename: Yeonseok
authors.initials: Y
authors.lastname: Chung
authors.forename: Sung-Youl
authors.initials: SY
authors.lastname: Ko
authors.forename: Hyun-Jeong
authors.initials: HJ
authors.lastname: Ko
authors.forename: Chang-Yuil
authors.initials: CY
authors.lastname: Kang
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000941:Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes; D019013:CD40 Antigens / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D007108:Immune Tolerance; D007422:Intestines / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000941:Antigens; D019013:CD40 Antigens; D010047:Ovalbumin