The role of self-antigen in the development of autoimmunity in Obese strain chickens with spontaneous autoallergic thyroiditis.

Neonatal thyroidectomy of Obese strain (OS) chickens showed that the spontaneous development of thyroid autoimmunity in these animals was fully dependent upon the presence of autoantigen, and could not be ascribed essentially to antigen-independent mechanisms such as polyclonal lymphocyte activation or innate distortions within the idiotype network. Similarly, removal of the gland in animals with established thyroiditis demonstrated the need for antigen to maintain the autoimmune response. Thyroglobulin from normal chickens induced autoantibodies in neonatally thyroidectomized OS birds, suggesting that an abnormality in the structure of this protein is not a prerequisite for the development of autoimmunity. This contention is supported by the finding that OS and normal thyroglobulin were immunochemically indistinguishable, whether compared using OS autoantibodies or rabbit anti-chicken thyroglobulin sera.