Immune response of mice transgenic for human histocompatibility leukocyte Antigen-DR to human thyrotropin receptor-extracellular domain

Thyroid. 2009 Nov;19(11):1271-80. doi: 10.1089/thy.2008.0349.


Background: Hyperthyroidism of Graves' disease is caused by auto-antibodies to human thyrotropin receptor (hTSH-R). To elucidate important T-cell epitopes in TSH-R, we studied three models of immunity to TSH-R in mice.

Methods: Mice transgenic for histocompatibility leukocyte antigen DR3 or DR2 were immunized with cDNA for hTSH-R-extracellular domain (hTSH-R-ECD), or hTSH-R-ECD protein, or hTSH-R peptide epitopes. Proliferative responses of immunized splenocytes to epitopes derived from the hTSH-ECD sequence, anti-TSH-R antibody responses, serum thyroxine and TSH, and thyroid histology were recorded.

Results: DR3 mice responded to genomic immunization with proliferative responses to several epitopes, which increased in intensity and spread to include more epitopes, during a 6-week immunization program. DR2 transgenic mice developed weak proliferative responses. Both types of mice developed anti-TSH-R antibodies measured by enzyme-linked immunosorbent assay or TSH-binding inhibition assay in 16-60% of animals. There was evidence of weak thyroid stimulation in one group of animals. Immunization of DR3 transgenic mice to hTSH-R-ECD protein induced a striking response to an epitope with sequence ISRIYVSIDVTLQQLES (aa78-94). Immunization to peptides derived from the TSH-R-ECD sequence (including aa78-94) caused strong responses to the epitopes, and development of immune responses to several other nonoverlapping epitopes within the hTSH sequence (epitope spreading) and antibodies reacting with hTSH-R. This implies that immunization with hTSH-R epitopes produced immunity to mouse TSH-R.

Conclusion: T-cell and B-cell responses to genetic immunization differ in DR3 and DR2 transgenic mice, and there is less genetic control of antibody than of T-cell responses. During both genomic and peptide epitope immunization there was evidence of epitope spreading during the immunization. Several functionally important epitopes are evident, especially aa78-94. However, if similar progressive epitope recruitment occurs in human disease, epitope-based therapy will be difficult to achieve.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Autoantibodies / genetics
  • Autoantibodies / immunology
  • B-Lymphocytes / immunology
  • Cell Proliferation
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes, B-Lymphocyte / genetics
  • Epitopes, B-Lymphocyte / immunology
  • Epitopes, T-Lymphocyte / genetics
  • Epitopes, T-Lymphocyte / immunology*
  • HLA-DR2 Antigen / genetics
  • HLA-DR2 Antigen / immunology*
  • HLA-DR3 Antigen / genetics
  • HLA-DR3 Antigen / immunology*
  • Humans
  • Immunization
  • Mice
  • Mice, Transgenic
  • Molecular Sequence Data
  • Receptors, Thyrotropin / administration & dosage*
  • Receptors, Thyrotropin / genetics
  • Receptors, Thyrotropin / immunology*
  • Staining and Labeling
  • T-Lymphocytes / immunology
  • Thyroid Gland / immunology


  • Autoantibodies
  • Epitopes, B-Lymphocyte
  • Epitopes, T-Lymphocyte
  • HLA-DR2 Antigen
  • HLA-DR3 Antigen
  • Receptors, Thyrotropin