Augmentation of thyroid-stimulating antibody-stimulated cyclic adenosine monophosphate response by polyethylene glycol, polyvinyl alcohol, and dextran; Highly sensitive porcine thyroid cell thyroid-stimulating antibody assay

Previously, we reported that 5% polyethylene glycol (PEG) (6000) augmented thyroid-stimulating antibody (TSAb)-stimulated cyclic adenosine monophospha te (cAMP) production in porcine thyroid cell (PTC) assay. This augmentation by PEG was specific to TSAb-stimulation. In this study we examined the eff ects of nonionic hydrophilic polymers such as PEG, polyvinyl alcohol (PVA), and dextran (DEX) on TSAb-stimulated cAMP production. We demonstrated that graded doses of PEG, PVA, and DEX augmented TSAb-stimulated cAMP productio ns; the prominent augmentations were observed with 5% PEG (20,000), 5% PEG (6000), 6% PEG (4000), 10% PVA, 14% DEX T-250, and 14% DEX T-70. PVA did no t augment thyrotropin (TSH)-stimulated cAMP synthesis. Five percent PEG (20 ,000), 14% DEX T-250, and 14% DEX T-70 augmented TSH-stimulated cAMP synthe sis very slightly. PEG, PVA, and DEX had no effects on the cAMP synthesis s timulated by GTP gamma S, forskolin, or pituitary adenylate cyclase activat ing polypeptide (PACAP), which stimulated adenylate cyclase. We also demons trated that PEG, PVA, and DEX augmented the cAMP responses stimulated by sm all amounts (50 mu L) of sera from Graves' patients; small amounts (50 mu L ) of sera could be used instead of purified immunoglobulin G (IgG). This ma y simplify the TSAb assay. We developed a highly sensitive simplified TSAb assay. PEG weakly augmented TSAb binding to isolated TSH receptor (thyrotro pin-binding inhibitor immunoglobulin [TBII] increased slightly). The mechan isms of the augmentations of TSAb-stimulated cAMP productions by PEG, PVA, and DEX is not simply explained by increased binding of TSAb to the recepto rs. Some factors that enhance TSAb action at the receptor site are suggeste d.