A combination of necrosis of autologous thyroid gland and injection of lipopolysaccharide induces autoimmune thyroiditis.

Autoimmune thyroiditis was induced in CBA/J female mice by a newly developed method consisting of intraperitoneal implantation of one whole syngeneic thyroid gland with subsequent intravenous injection of lipopolysaccharide (LPS). The best timing for intravenous injection of LPS after intraperitoneal implantation of the thyroid tissue was 6 hr. Intraperitoneal injection of serum (but not spleen cells) taken from the mice which received implantation of one whole syngeneic thyroid gland alone, with simultaneous intravenous injection of LPS, induced autoimmune thyroiditis in the normal syngeneic mice. Furthermore, intraperitoneal injection of the medium in which one whole syngeneic thyroid gland was incubated at 37 degrees C for 10 hr, with simultaneous intravenous injection of LPS, also induced autoimmune thyroiditis in the normal syngeneic mice. Instead of intraperitoneal implantation of one whole syngeneic thyroid gland, implantation of either one lobe of autologous thyroid under the capsule of the kidney, with subsequent intravenous injection of LPS induced autoimmune thyroiditis in both intact and implanted thyroids. It is suggested that combined effects of leakage of tissue antigen originating from the necrotized tissue into the circulation and polyclonal activation by subsequent injection of LPS induced an autoimmune response.