title: Cognate CD4+ help elicited by resting dendritic cells does not impair the induction of peripheral tolerance in CD8+ T cells.
abstract: Peripheral tolerance is required to prevent autoimmune tissue destruction by self-reactive T cells that escape negative selection in the thymus. One mechanism of peripheral tolerance in CD8(+) T cells is their activation by resting dendritic cells (DC). In contrast, DC can be "licensed" by CD4(+) T cells to induce cytotoxic function in CD8(+) T cells. The question that then arises, whether CD4(+) T cell help could impair peripheral tolerance induction in self-reactive CD8(+) T cells, has not been addressed. In this study we show that CD4(+) T cell activation by resting DC results in helper function that transiently promotes the expansion and differentiation of cognate CD8(+) T cells. However, both the CD4(+) and CD8(+) T cell populations ultimately undergo partial deletion and acquire Ag unresponsiveness, disabling their ability to destroy OVA-expressing pancreatic beta cells and cause diabetes. Thus, effective peripheral tolerance can be induced by resting DC in the presence of CD4(+) and CD8(+) T cells with specificity for the same Ag.
authors.affiliation: Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia. rsteptoe@cicr.uq.edu.au
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Steptoe
authors.forename: Janine M
authors.initials: JM
authors.lastname: Ritchie
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Wilson
authors.forename: Jose A
authors.initials: JA
authors.lastname: Villadangos
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Lew
authors.forename: Leonard C
authors.initials: LC
authors.lastname: Harrison
mesh_terms: D000818:Animals; D000941:Antigens / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D017637:Clonal Deletion / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D007108:Immune Tolerance; D050417:Insulin-Secreting Cells / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000235:genetics / Q000276:immunology
chemical_list: D000941:Antigens; D010047:Ovalbumin