Immunohistochemical demonstration of thyrotropin (TSH)-receptor in normal and diseased human thyroid tissues using monoclonal antibody against recombinant human TSH-receptor protein.

We performed an immunohistochemical analysis of TSH-receptor in normal and diseased human thyroid tissues using a monoclonal antibody (T3-356) against the C terminal region of human TSH receptor. In normal human thyroid tissues, a positive staining was observed exclusively along the basal cell surface of the flattened follicular cells. In the tissues from adenomatous nodules, adenomas, and papillary carcinomas, a positive staining was also found along the basal cell surface of the follicular cells. In addition, a considerable cytoplasmic staining was observed. The apical and lateral cell surfaces of the follicular cells showed no staining. The foci of squamous cell metaplasia of papillary carcinomas, anaplastic carcinoma, and medullary carcinoma did not show a positive staining. In Graves' thyroids, the positive staining was also observed along the basal cell surface of the follicular cells. The staining was obviously intense in the Graves' thyroids, and the most intense staining was noted in the foci of papillary projection of the columnar follicular cells. These findings indicate that TSH receptor is preserved essentially in the basal cell surface of the thyroid follicular cells in neoplastic conditions and that the amount of TSH receptor protein is increased in Graves' thyroid.