Comparison of thyroid antigens by the experimental production of precipitating antibodies to human thyroid fractions and the identification of an antibody which competes with long-acting thyroid stimulator (LATS) for thyroid binding.

Antibodies were raised to various sub-cellular fractions of human thyroids, (of Graves' disease, Hashimoto's thyroiditis, and non-toxic goitre). With one exception it was found that antibodies to the Graves' thyroid fractions crooss-reacted with both the non-toxic goitre and Hashimoto's thyroiditis fractions. This exception was in the antiserum to the Graves' 105 000 x g pellet (Gr4) which contained an anr the Hashimoto's (/) thyroid preparations. The antibody-antigen between A-1 and Gr4 could be blocked by the addition of LATS (or TSH) to the antigen, thus suggesting that A- 1 might be a LATS-like immunoglobulin. These results suggest that the TSH receptor can be produced in vivo. Production of such an antibody to the TSH receptor would permit the development for the first time fo a good animal model of Graves' disease.