title: Peripheral Proinsulin Expression Controls Low-Avidity Proinsulin-Reactive CD8 T Cells in Type 1 Diabetes.
abstract: Low-avidity autoreactive CD8 T cells (CTLs) escape from thymic negative selection, and peripheral tolerance mechanisms are essential for their regulation. We report the role of proinsulin (PI) expression on the development and activation of insulin-specific CTLs in the NOD mouse model of type 1 diabetes. We studied insulin B-chain-specific CTL from different T-cell receptor transgenic mice (G9Cα-/-) expressing normal PI1 and PI2 or altered PI expression levels. In the absence of PI2 (Ins2-/-), CTL in pancreatic lymph nodes (PLNs) were more activated, and male G9Cα-/-mice developed T1D. Furthermore, when the insulin-specific CTLs developed in transgenic mice lacking their specific PI epitope, the CTLs demonstrated increased cytotoxicity and proliferation in vitro and in vivo in the PLNs after adoptive transfer into NOD recipients. Dendritic cell-stimulated proliferation of insulin-specific T cells was reduced in the presence of lymph node stromal cells (LNSCs) from NOD mice but not from mice lacking the PI epitope. Our study shows that LNSCs regulate CTL activation and suggests that exposure to PI in the periphery is very important in maintenance of tolerance of autoreactive T cells. This is relevant for human type 1 diabetes and has implications for the use of antigen-specific therapy in tolerance induction.
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Terri C
authors: TC
authors: Thayer
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: James A
authors: JA
authors: Pearson
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Evy
authors: E
authors: De Leenheer
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Stephanie J
authors: SJ
authors: Hanna
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Joanne
authors: J
authors: Boldison
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Joanne
authors: J
authors: Davies
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Adrian
authors: A
authors: Tsui
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Sartaj
authors: S
authors: Ahmed
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Peter
authors: P
authors: Easton
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K.
authors: Lai Khai
authors: LK
authors: Siew
authors: Section of Endocrinology, Yale School of Medicine, New Haven, CT.
authors: Li
authors: L
authors: Wen
authors: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff University, Cardiff, U.K. wongfs@cardiff.ac.uk.
authors: F Susan
authors: FS
authors: Wong
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000378:metabolism*; D000939:Epitopes / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D007328:Insulin / Q000378:metabolism; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011384:Proinsulin / Q000378:metabolism*
chemical_list: D000939:Epitopes; D007328:Insulin; D011384:Proinsulin