HLAandH2Class II Transgenic Mouse Models to Study Susceptibility and Protection in Autoimmune Thyroid Disease

Abstract

Using single H2 and HLA class II transgenic mice, in the absence of endogenous H2 class II molecules, we have studied the permissiveness of class II molecules for experimental autoimmune thyroiditis (EAT). Resistant strains expressing susceptible class II molecules, H2Ak or HLA-DR3, developed EAT, clearly demonstrating the importance of class II gene inheritance. Polymorphism for HLA-DRB1 was observed, as DR3, but not DR2 or DR4, molecules were permissive for EAT induction with either mouse (m) or human (h) thyroglobulin (Tg). HLA-DQ polymorphism was also detectable, as hTg-induced EAT developed in DQ8+, but not DQ6+, mice. Class II gene interactions leading to reduced EAT severity were observed in H2 transgenic mice, when H2E transgene was expressed in H2A+ mice or H2A molecules were introduced into our novel H2A- E+ transgenic model. Similarly, in DR3+ mice, only the DQ8 transgene reduced EAT severity, depending on both background genes (C57BL/10 or NOD) and Tg species. Based on computer-predicted, class II-binding motifs, potential pathogenic Tg peptides, either unique to hTg (H2A- E+ model) or shared between mTg and hTg (HLA-DR3+ model), were identified. We have also developed a Graves' disease model by immunizing DR3+ mice with TSH receptor DNA. Thus, transgenic models are excellent tools to study human autoimmune thyroid diseases in the context of murine EAT.

A novel H2A−E+ transgenic model susceptible to human but not mouse thyroglobulin-induced autoimmune thyroiditis: Identification of mouse pathogenic epitopes

“…Peptide hTg410 was previously found to be pathogenic in the A − E + mouse; not only did it activate splenocytes to transfer thyroiditis to naive mice, it also induced mild thyroiditis upon direct immunization [9]. Since the corresponding mouse peptide, mTg409, was found to be immunogenic, we tested whether T cells primed to either peptide could cross-react with the corresponding peptide.…”

“…2A). While none of the hTg-derived peptides constituted an immunodominant epitope, each was recognized by hTg-primed A − E + T cells, and hTg410, and to a lesser extent hTg2344, were pathogenic, as they activated hTg-primed splenocytes for thyroiditis transfer to naive animals [9]. Each mTg peptide had at least 2 of 4 predicted anchor residues for H2E b [19,20], and were designated mTg409, mTg1241, and mTg2342.…”

“…The mTg and hTg sequences were previously searched for H2E b -binding peptides, and three hTg peptides (15-to 16-mer) were confirmed immunogenic [9]. For this study, the corresponding mTg-derived peptides were also synthesized ( Fig.…”

“…The necessity of thyroidal Ag presentation was verified by the inability of hTg-primed and -activated cells to transfer thyroiditis to MHC class II-deficient mice [8]. Preliminary studies searching for H2E b -binding peptides of hTg identified three immunogenic sites on hTg [9]. These peptides were H2E b -restricted, stimulated hTg-primed T cells in vitro, and two were thyroiditogenic.…”

H2E-Derived Eα52-68 Peptide Presented by H2Ab Interferes with Clonal Deletion of Autoreactive T Cells in Autoimmune Thyroiditis

“…mTg1677 was further shown to be pathogenic. We also tested a peptide, mTg2342, synthesized as a corresponding epitope of the E b -restricted hTg peptide hTg2344 (25). We found it to be immunogenic in A ϩ E Ϫ and A ϩ E ϩ mice, and A b -restricted.…”