T and B cell reactivity in experimental autoimmune thyroiditis.

Using several immunization protocols, T cells specific for self Tg were shown to be activated to only a limited degree compared with the ability to activate T cells to a foreign Tg. Thus, a high degree of tolerance exists in T cells to self Tg, while tolerance is not maintained in B cells. Whether the small degree of T cell activation that is induced under stringent immunization procedures plays a role in the induction of the spontaneous disease is unknown. Preliminary results are also presented showing that experimental autoimmune thyroiditis (EAT) can be more readily induced in aged than in young adult mice and these results are discussed in terms of the generalized decrease in T cell reactivity in aged mice.