Thyroid-Stimulating Immunoglobulin Bioassay Using Cultured Human Thyroid Cells*

Abstract

Modifications are described in the cultured thyroid cell cAMP assay for TSH which make it suitable for the measurement of thyroid-stimulating immunoglobulins. Comparison was made between this assay and two others measuring cAMP responsiveness in human thyroid tissue, namely the thyroid slice and thyroid plasma membrane adenylate cyclase assays, all performed with the same tissue sample. Of immunoglobulin G (IgG) samples from 7 unselected patients with untreated hyperthyroidism associated with Graves' disease, 5 produced significant stimulation of cAMP content in cultured thyroid cells when compared to pooled normal IgG. None of these 7 produced a statistically significant increase in thyroid slice cAMP content when assayed in triplicate, the same replicate number used in the cultured thyroid cell assay. Similarly, none of the same Graves' IgG samples produced significant stimulation (vs. control IgG) in the membrane adenylate cyclase assay, in which sensitivity to TSH stimulation was very poor. With a scaled-down modification of the assay using microtiter wells and acetylation to enhance detection of cAMP in the RIA, significant TSI activity was observed in 15 of 18 (83%) IgG samples from patients with untreated Graves' disease. The data indicate the excellent sensitivity and precision of the thyroid cell cAMP assay, as well as its convenience.

Generation of recombinant, enzymatically active human thyroid peroxidase and its recognition by antibodies in the sera of patients with Hashimoto's thyroiditis.

“…Human Graves' disease thyroid tissue was dispersed and the cells were cultured as previously described (37 …”

Thyrotropin-Blocking Autoantibodies and Thyroid-Stimulating Autoantibodies: Potential Mechanisms Involved in the Pendulum Swinging from Hypothyroidism to Hyperthyroidism or Vice Versa

“…Bioassays for TSAb initially employed human thyroid cell monolayers and measured the ability of TSHR autoantibodies or TSH to increase intracellular cAMP levels (14,15). A rat …”

Gamma-interferon activates a nuclear protein that binds to the gamma-interferon activation site of the thyroglobulin gene

“…Normal para-adenomatous human thyroid tissues obtained from subjects undergoing hemithyroidectomy were enzymatically digested and cultured in R.p.m.I-1640 medium supplemented with 10% fetal calf serum (Hinds et al 1981). These cells had been confirmed previously to respond to TSH stimulation by the production of cAMP and release of tri-iodothyronine and Tg.…”