Susceptibility and resistance to experimental autoimmune thyroiditis is encoded by MHC H2A genes. We reported that traditionally resistant BIO (H2 b) mice permit thyroiditis induction with mouse thyroglobulin (mTg) after depleting regulatory T cells (Tregs), supporting Ab presentation to thyroiditogenic T cells. Yet, Eak transgenic mice, expressing Ab and normally absent Eb molecules (E +B10 mice), are susceptible to thyroiditis induction without Treg depletion. To explore the effect of Eb expression on mTg presentation by A b, seven putative Ab-binding, 15-16-mer peptides were synthesized. Five were immunogenic for both BIO and E+B10 mice. The effect of Eb expression was tested by competition with an Eα52-68 peptide, because Eα52-68 occupies ∼15% of Ab molecules in E+B10 mice, binding with high affinity. Eα52-68 competitively reduced the proliferative response to mTg, mTgl677, and mTg2342 of lymph node cells primed to each Ag. Moreover, mTgl677 induced mild thyroiditis in Treg-depleted BIO mice, and in E+B10 mice without the need for Treg depletion. Eα52-68 competition with mTg-derived peptides may impede clonal deletion of pathogenic, mTg-specific T cells in the thymus.
ASJC Scopus subject areas
- Immunology and Allergy