INFLUENCE OF DIET ON THE INDUCTION OF EXPERIMENTAL AUTOIMMUNE THYROID-DISEASE

Immunization of CBA/J mice with thryoglobulin (Tg) emulsified in compl ete Freund's adjuvant induces experimental thyroiditis (EAT), a well-c haracterized model of Hashimoto's disease, Recent studies have suggest ed that dietary factors play a role in the modulation of the immune re sponse and that diet can have a profound effect an the induction of au toimmune diseases, In this study, we examined the influence of diet on autoimmune thyroiditis in mice, EAT was induced in mice fed ad libitu m one of the three diets, a standard maintenance chow (Agway H1000), P urina 5020 Breeding Chow, and Purina 5010 Autoclavable: (unautoclaved) Diet. Tg-immunized mice fed the Agway 1000 diet were found to be resi stant to the development of autoimmune thyroid disease, with only 4 ou t of 25 mice developing mild thyroiditis. In contrast, 16 out of 25 mi ce fed the Purina 5010 diet developed moderate to severe thyroiditis. Mice fed the 5020 diet were partly susceptible: 7 out of 25 developed a mild to moderate thyroiditis, Histologic examination of thyroid glan ds of diseased mice fed the 5010 and 5020 diets showed marked lymphocy tic infiltration with destruction of follicles, compared with mice fed the Agway diet, the latter showing only mild infiltration with preser vation of thyroid follicles, Titers of antibody to Tg did not differ a mong the groups, and there was no significant difference in the IgG Is otype subclass usage. The results demonstrate that diet can markedly a ffect the severity of autoimmune disease in the EAT model, In contrast , diet has little effect on the humoral autoimmune response In this sy stem. These results implicate diet as a factor in the severity of cell -mediated autoimmune destruction and suggest that dietary modification could decrease pathology in some forms of autoimmune disease.