Insulin-dependent diabetes mellitus (IDDM) is one of the most common autoimmune diseases in humans. Environmental and genetic factors combine to bring about the onset the disease. The mechanism of initiation of T cell activation is still unknown, but a number of islet beta cell-expressed proteins have been shown to be targeted. Susceptibility to IDDM is most strongly determined by DQ/I-A beta MHC class II molecules which contain serine, alanine, or valine at position 57. We propose to address and characterize in depth, molecular aspects of the autoimmune process leading to beta cell destruction in the NOD mouse, the best characterized model of diabetes. Our approach is to produce IA-peptide complexes and their T cell receptors and carry out functional, structural, and in vivo experiments. We will express and purify the unique MHC class II molecule of the NOD mouse, I-Ag7 using a Drosophila melanogaster expression system with which we have had success with many other immunological molecules. The purified molecules will be used to characterize both peptide and invariant chain binding, and also for crystallization trials and x-ray structure determination. Two T cell receptors, BDC2.5 and R28, which are restricted on this molecules will also be expressed in a soluble form in the fly system. Both of these TCRs are pathogenic in transgenic mice and BDC2.5 causes insulitis and diabetes. The autoantigens for these 2 TCRs are still unknown. One of our aims is to determine which peptide(s) these 2 TCRs recognize in the context of I-Ag7. In vitro selection by phage display will be used to determine the natural ligands and to construct mimics, or mimotopes, of these ligands. Natural ligands and mimotopes in association with I-Ag7 will be used to measure the affinity of BDC2.5 and R28. We will attempt to crystallize and collaboratively determine the crystal structures these TCRs and TCR/p-MHC complexes. Soluble I- Ag7 peptide molecules will also be used to attempt to induce apoptosis and deletion of specific T cells in a TCR transgenic mouse and in a double transgenic diabetic mouse. Depending on the success of these experiments, treatment will be attempted in the NOD mouse for the prevention of islet graft rejection. This proposal should provide a great deal of functional and structural information about I-Ag7 molecules and their interactions with autoimmune TCRs.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK055037-01
Application #
2756728
Study Section
Immunological Sciences Study Section (IMS)
Program Officer
Akolkar, Beena
Project Start
1999-01-01
Project End
2003-11-30
Budget Start
1999-01-01
Budget End
1999-11-30
Support Year
1
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Yoshida, Kenji; Corper, Adam L; Herro, Rana et al. (2010) The diabetogenic mouse MHC class II molecule I-Ag7 is endowed with a switch that modulates TCR affinity. J Clin Invest 120:1578-90
Landais, Elise; Romagnoli, Pablo A; Corper, Adam L et al. (2009) New design of MHC class II tetramers to accommodate fundamental principles of antigen presentation. J Immunol 183:7949-57
Depaolo, R William; Tang, Fangming; Kim, Inyoung et al. (2008) Toll-like receptor 6 drives differentiation of tolerogenic dendritic cells and contributes to LcrV-mediated plague pathogenesis. Cell Host Microbe 4:350-61
Hovhannisyan, Zaruhi; Weiss, Angela; Martin, Alexandra et al. (2008) The role of HLA-DQ8 beta57 polymorphism in the anti-gluten T-cell response in coeliac disease. Nature 456:534-8
Homann, Dirk; Lewicki, Hanna; Brooks, David et al. (2007) Mapping and restriction of a dominant viral CD4+ T cell core epitope by both MHC class I and MHC class II. Virology 363:113-23
Brooks, David G; Teyton, Luc; Oldstone, Michael B A et al. (2005) Intrinsic functional dysregulation of CD4 T cells occurs rapidly following persistent viral infection. J Virol 79:10514-27
Ranheim, Erik A; Tarbell, Kristin V; Krogsgaard, Michelle et al. (2004) Selection of aberrant class II restricted CD8+ T cells in NOD mice expressing a glutamic acid decarboxylase (GAD)65-specific T cell receptor transgene. Autoimmunity 37:555-67
Robey, Ian F; Peterson, Melissa; Horwitz, Marc S et al. (2004) Terminal deoxynucleotidyltransferase deficiency decreases autoimmune disease in diabetes-prone nonobese diabetic mice and lupus-prone MRL-Fas(lpr) mice. J Immunol 172:4624-9
Stratmann, Thomas; Martin-Orozco, Natalia; Mallet-Designe, Valerie et al. (2003) Susceptible MHC alleles, not background genes, select an autoimmune T cell reactivity. J Clin Invest 112:902-14
Mallet-Designe, Valerie I; Stratmann, Thomas; Homann, Dirk et al. (2003) Detection of low-avidity CD4+ T cells using recombinant artificial APC: following the antiovalbumin immune response. J Immunol 170:123-31

Showing the most recent 10 out of 17 publications