Abstracts controls. For stimulation specific amino acid sequences of glutamic acid decarboxylase 65 (GAD65), thyrosine phosphatase (IA2), beta-proinsulin chain and whole molecule of insulin were used. Cell activation was measured by surface expression of interferon gamma (IFN-g) on activated CD4+ T cells. High-risk relatives of T1D patients have significantly lower pre- and post-stimulatory numbers of Tregs than healthy controls (p b 0.05). The autoantigen activation of diabetogenic T cells was significantly higher in high-risk relatives of T1D patients than in healthy controls (p b 0.02). In conclusion, defects of CD4+CD25+ regulatory T cells have been proved in individuals at increased genetic risk for T1D. Supported by IGA MZCR NR 9355-3. doi:10.1016/j.clim.2007.03.232
F.20 Differential Immune Recognition of Heat-Shock Protein 60 Epitopes in Type 1 Diabetes Sylvia Kamphuis, Pediatric Immunologist, Department of Paediatric Immunology, Erasmus MC Sophia Children’s Hospital, Rotterdam, Gijs Teklenburg, MD, Pediatric Immunology, UMC Utrecht, Utrecht, Annemarie Verrijn Stuart, Pediatric Endocrinologist, Department of Pediatric Endocrinology, UMC Utrecht, Utrecht, Irun Cohen, MD PhD, Department of Immunology, Weizmann Institute of Science, Rehovot, Wilco de Jager, Msc, Department of Immunology, UMC Utrecht, Utrecht, Wietse Kuis, MD PhD, Department of Immunology, UMC Utrecht, Utrecht, Salvatore Albani, MD PhD, Department of Pediatrics and Medicine, University of California, San Diego, CA, Berent Prakken, MD PhD, Department of Immunology, UMC Utrecht, Utrecht, Mark Klein, Msc, Department of Immunology, UMC Utrecht, Utrecht Aim: Evidence is cumulating for an immunoregulatory role of heat-shock proteins (HSP) in an increasing number of autoimmune diseases. Previously we identified pan-DR binding HSP60 epitopes that were recognized in juvenile idiopathic arthritis, an autoimmune disease characterized by chronic joint inflammation. The present study was performed to test whether these HSP60 epitopes were recognized in children with type 1 diabetes as well. Methods: We analyzed the pattern of HSP60 peptide-specific cytokine and chemokine responses in peripheral blood mononuclear cells of 18 type 1 diabetes patients with primarily longstanding disease. In addition, a subgroup of newly diagnosed patients was followed over time for HSP60 peptide-specific immune responses. Results: We found peptide-specific induction of 8 cytokines (IL-1a, IL-1b, IL-6, IL-10, IL-17, IL-18, TNF-a, IFN-g) and 5 chemokines (MIP-1a, MDC, IL-8, IP10, and OSM). Considerable variation in peptide-induced cytokine and chemokine profiles however was seen in the individual patients, irrespective of age and disease duration. When following newly diagnosed patients over time, we found that the presence of T cell proliferative responses was almost exclusively seen in the patients that experienced a partial remission phase, with concomitant induction of IL-10. Conclusion: The identified HSP60 epitopes are immunogenic in children with type 1 diabetes. The recorded correlation of peptide-specific T cell responses with (temporary) disease remission underscores the alleged immunomodulating role of HSP in chronic inflammation. This makes these HSP60 epitopes promising candidates
S23 for antigen-specific immunotherapy in not only juvenile idiopathic arthritis, but also in type 1 diabetes and possibly other autoimmune diseases. doi:10.1016/j.clim.2007.03.233
F.21 Blocking the Toll Like Receptor 9 Signal Inhibits Activation of Diabetogenic CD8 T Cells and Delays Autoimmune Diabetes in NOD Mice Yiqun Zhang, Research Associate, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada, Xuan Geng, Research Assistant, Kinesiology, Simon Fraser University, Burnaby, BC, Canada, Pere Santamaria, Professor, Microbiology and Infectious Diseases, The University of Calgary, Calgary, AB, Canada, Diane Finegood, Professor, Kinesiology, Simon Fraser University, Burnaby, BC, Canada, Jan P. Dutz, Professor, CFRI, University of British Columbia, Vancouver, BC, Canada Type 1 diabetes is an autoimmune disease in which pancreatic beta cells are destroyed by CD8 T cells. Dendritic cells (DC)s are capable of priming CD8 Tcells. Toll-like receptor (TLR) triggering can lead to DC maturation. The contributions of TLR signals to spontaneous diabetes development are still largely unknown. We found that non-obese diabetic (NOD) mouse bone marrow derived DCs (BMDC)s pulsed with freeze–thawed NIT1 insulinoma cells in the presence of TLR9 agonist CpG and CD40 ligation were able to fully prime 8.3 TCR transgenic and diabetogenic CD8 T cells. Addition of the TLR9 inhibitors ODN 2088 or chloroquine potently inhibited CD8 T cell CD25 upregulation and intracellular IFN-γ production in response to CPG but not LPS. Furthermore, ODN 2088 or chloroquine inhibited CPG-induced BMDC CD40 upregulation and IL-12 p70 production. In vivo, CPG alone or with anti-CD40 induced 8.3 CD8 T cell CD69 upregulation and CTL activity that triggered rapid diabetes development in 8.3 NOD mice. Pre-treatment with ODN 2088 inhibited CPG-induced diabetes and treatment with either ODN 2088 or chloroquine delayed spontaneous diabetes in 8.3 NOD mice. Finally, administration of chloroquine inhibited spontaneous diabetes in NOD mice, down-regulated CD40 expression on pancreatic DCs, and inhibited serum rises of IL-12 p70, IL-6, IFN-γ and MCP-1 induced by CPG but not LPS. Thus, TLR9 activation may contribute to the spontaneous onset of CD8 T cell autoimmunity in NOD mice and TLR9 family inhibitors may be used to prevent and delay autoimmune diabetes in disease-prone animals. doi:10.1016/j.clim.2007.03.234
F.22 Genome-Wide Association Scan for Type 1 Diabetes Susceptibility Genes in a Danish Population Caroline Brorsson, PhD Student, Steno Diabetes Center, Gentofte, Elzbieta Swiergala, Lab Manager, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada, Kristoffer Rapacki, Computer Scientist, Center for Biological Sequence Analysis, Technical University of Denmark, Lyngby, Regine Bergholdt, Research Fellow, Steno Diabetes Center, Gentofte, Shaun Purcell, Assistant Professor, Center for Human Genetic Research,