Thyroid-stimulating antibodies in Grave's disease and the effect of thyrotrophin-binding globulins on their determination.
Globulin preparations from the sera of 104 untreated patients with Grave's disease have been tested for their thyroid-stimulating antibody (TSAb) activities. Eighty-one of the samples (78%) were positive in the assay for the thyrotrophin-binding inhibitory immunoglobulins, 48 samples (46%) contained human thyroid adenyl cyclase stimulators (HTACS) and 71 (68%) contained human thyroid stimulators (HTS) measured as stimulation of colloid droplet formation in human thyroid slices. All 104 samples were positive in one or other of the assays, 29 (28%) were positive in all three assays and 38 (37%) in two. All samples were tested for their specific TSH-binding characteristics, 40 (38%) possessed 'B-type' binding sites (previously characterized as TSH-binding sites with low affinity but high capacity for the ligand) but the remaining 64 samples (62%) were no different from normal control samples and had 'A-type' binding sites (high affinity but low capacity binding sites for TSH). Samples without detectable thyrotrophin-binding inhibitory immunoglobulin did not contain B-type TSH-binding globulins. Globulins exhibiting B-type binding were more active in the HTACS and HTS assays. The B-type TSH-binding globulins have a characteristic, dose-dependent reducing effect on the human thyroid adenyl cyclase stimulation by TSH whereas A-type globulins do not. Globulins exhibiting B-type TSH-binding may therefore have a significant effect on assays for TSAb activities. The method used to measure TSAb have been reviewed from this point of view.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000906:Antibodies / Q000032:analysis*; D006111:Graves Disease / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D018828:Immunoglobulins, Thyroid-Stimulating; D011869:Radioligand Assay; D013961:Thyroid Gland / Q000201:enzymology / Q000276:immunology*; D013972:Thyrotropin / Q000378:metabolism
D000906:Antibodies; D007074:Immunoglobulin G; D018828:Immunoglobulins, Thyroid-Stimulating; D013972:Thyrotropin; D000262:Adenylyl Cyclases