Autoantibodies to the thyrotropin receptor can either activate thyroid gland causing hyperthyroidism or block TSH mediated activation of thyroid and cause hypothyroidism. Until several years ago, it was not possible to develop an animal mode due to the unavailability of large quantities of purified TSHR. Subsequent to cloning of human TSHR, several laboratories, including our own, have used human recombinant proteins to induce the disease in mice. These studies have provided new insights on the requirements for an optimal immune response to TSHR, resulting in thyroid perturbation. Earlier, we expressed the ectodomain of mouse TSHR (mTSHR) and showed that it is antigenically distinct from human TSHR. Recently, we expressed mTSHR on M12 cells (H-2D) and used them to immunize BALB/c mice. These mice showed significant TBII activity with concomitant raise in T4 levels. In the present study, we propose to use a soluble ectodomain of mTSHR and various cell lines expressing mTSHR, Class-II and Co-stimulatory molecules to define optimal conditions required to induce autoimmunity to TSHR. Sera will be tested for antibody production and hormonal perturbations, and thyroids will be evaluated for pathology and radioiodine uptake. We will carryout studies to evaluate the importance of CD4+ vs. CD8+ and Th1 vs. Th2 T cells. To do this, we will use selective depletion and adoptive transfer experiments, determine the relevance of cytokines, and test the ability of the protein to induce disease in Class-I and II, IFNgamma, and IL4 knockout mice available on BALB/c background. To define TSHR epitopes to which pathogenic antibodies bind, we will carryout epitope mapping studies. For this, we will employ recombinant fragments of TSHR, ectodomains of TSHR-LH/CGR chimeric proteins and cells expressing these chimeras. These proteins or their fragments will be tested in a number of different serological and bioassays. Together these studies are expected to allow establishment of an appropriate animal model to study autoimmunity to TSHR. Such a model would facilitate a thorough understanding of the regulation of the immune response to TSHR with implications for the development of novel therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK047417-08
Application #
6624882
Study Section
Endocrinology Study Section (END)
Program Officer
Akolkar, Beena
Project Start
1995-06-01
Project End
2003-11-30
Budget Start
2002-12-01
Budget End
2003-11-30
Support Year
8
Fiscal Year
2003
Total Cost
$203,861
Indirect Cost
Name
University of Illinois at Chicago
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
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Gangi, Eryn; Kapatral, Vinayak; El-Azami El-Idrissi, Mohammed et al. (2004) Characterization of a recombinant Yersinia enterocolitica lipoprotein; implications for its role in autoimmune response against thyrotropin receptor. Autoimmunity 37:515-20
Vasu, Chenthamarakshan; Wang, Amy; Gorla, Seema R et al. (2003) CD80 and CD86 C domains play an important role in receptor binding and co-stimulatory properties. Int Immunol 15:167-75
Vasu, Chenthamarakshan; Holterman, Mark J; Prabhakar, Bellur S (2003) Modulation of dendritic cell function and cytokine production to prevent thyroid autoimmunity. Autoimmunity 36:389-96
Vasu, Chenthamarakshan; Dogan, Rukiye-Nazan E; Holterman, Mark J et al. (2003) Selective induction of dendritic cells using granulocyte macrophage-colony stimulating factor, but not fms-like tyrosine kinase receptor 3-ligand, activates thyroglobulin-specific CD4+/CD25+ T cells and suppresses experimental autoimmune thyroiditis. J Immunol 170:5511-22
Prasad, Kanteti V; Prabhakar, Bellur S (2003) Apoptosis and autoimmune disorders. Autoimmunity 36:323-30
Dogan, Rukiye-Nazan E; Vasu, Chenthamarakshan; Holterman, Mark J et al. (2003) Absence of IL-4, and not suppression of the Th2 response, prevents development of experimental autoimmune Graves' disease. J Immunol 170:2195-204
Cundiff, J G; Kaithamana, S; Seetharamaiah, G S et al. (2001) Studies using recombinant fragments of human TSH receptor reveal apparent diversity in the binding specificities of antibodies that block TSH binding to its receptor or stimulate thyroid hormone production. J Clin Endocrinol Metab 86:4254-60
Rao, S; Vasu, C; Martinez, O et al. (2001) Targeted delivery of anti-CTLA-4 antibody downregulates T cell function in vitro and in vivo. Clin Immunol 101:136-45

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