STUDIES ON THYROID CELL-SURFACE ANTIGENS USING CULTURED HUMAN THYROID-CELLS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 47  (2) , 336-344
Abstract
Human thyroid cells in primary culture were used for studies of thyroid cell surface antibodies in patients with thyroid autoimmune disorders. Radioiodinated IgG preparations containing thyroid microsomal antibody (TMAb), thyroid stimulating antibody (TSAb) and/or thyroglobulin antibody (TgAb) were tested for binding to thyroid cells. Binding was observed with radioiodinated IgG from patients with Graves'' disease, Hashimoto''s thyroiditis and idiopathic myxoedema containing TMAb, irrespective of the presence of TSAb and TgAb, while negative results were obtained with normal IgG. A dose-dependent inhibition of binding to thyroid cells was produced by the addition of the corresponding unlabeled IgG preparations. Evidence for tissue specificity was provided by the absence of binding to human skin fibroblasts used as controls. Preabsorption with human thyroid microsomes completely abolished the binding to thyroid cells of a radioiodinated TMAb positive IgG preparation, while only incomplete removal of the reactivity to thyroid microsomes was produced by preabsorption with thyroid cells. Some but not all microsomal antigenic determinants appear to be expressed on the thyroid cell surface. Binding to thyroid cells was also observed with purified TgAb, indicating that thyroglobulin antigenic determinants are present on the surface of thyroid cells. No evidence of binding was obtained with a TSAb positive Graves'' IgG preparation with undetectable TMAb and TgAb. Unlabeled IgG preparations containing TMAb from patients with either Hashimoto''s thyroiditis or idiopathic myxoedema inhibited the binding to thyroid cells of radioiodinated TMAb positive Graves'' IgG and vice versa. Thus, antibodies present in these thyroid autoimmune disorders apparently share common thyroid cell surface antigens. The binding of radioiodinated IgG from a patient with idiopathic myxoedema was only partially inhibited by Graves'' or Hashimoto''s IgG, suggesting that some of the thyroid cell surface antibodies of idiopathic myxoedema may not be detectable in other thyroid autoimmune disorders.