Using HLA-DR3-CBA/J Humanized Mice to Develop a Novel Genetic Model for Autoimmune Thyroiditis.

Abstract

BACKGROUND: Experimental autoimmune thyroiditis is an important animal model for studying Hashimoto's thyroiditis. Our aim was to develop the model using CBA/J-DR3 mice expressing human HLA-DR3, which is associated with autoimmune thyroiditis in humans, to better simulate human autoimmune thyroiditis. Such a humanized model can be used to test specific antigen therapies for autoimmune thyroiditis. METHODS: CBA/J-DR3 mice were produced by back-crossing B6-DR3 mice to the CBA/J background. Female CBA/J-DR3 mice were immunized with human thyroglobulin (Tg) in complete Freund's adjuvant on days 0 and 7. On day 21, mice were sacrificed, blood collected, spleen and thyroid harvested for analysis. Splenocytes were analyzed for T cell responses to Tg and its major T-cell epitope in human autoimmune thyroiditis, Tg.2098. Serum anti-thyroglobulin antibodies were measured by ELISA, and thyroid-stimulating hormone was measured using the Luminex assay. Thyroid histology and immunohistochemistry were examined. RESULTS: Immunized CBA/J-DR3 mice showed significant T cell proliferation in response to Tg (stimulation index 3.4 &#xb1; 4.5) and Tg.2098 (1.5 &#xb1; 0.7). Anti-thyroglobulin antibody levels were elevated in immunized mice when compared to control mice (2.05 &#xb1; 0.75 vs. 0.15 &#xb1; 0.06,< 0.0001). T cells demonstrated higher reactivity to thyroid antigens by enhanced production of pro-inflammatory cytokines. Thyroid immunohistochemistry revealed mild CD3-positive T-cell infiltration. CONCLUSIONS: This novel humanized CBA/J-DR3 mouse model of Hashimoto's thyroiditis demonstrates key features of human autoimmune thyroiditis. The HLA-DR3 background and the immune response to Tg and Tg.2098 enhance translational relevance, making this a valuable model for studying thyroid disease pathogenesis and testing targeted immune-modifying therapies.