Ochi Yukio, Hamazu Masanari, Kajita Yoshihiro, Hachiya Takashi, Miyata Takeshi, Barrett Carol, Smith Bernard Rees
Research Institute for Production Development, Kyoto, Japan.
Thyroid. 2009 Jan;19(1):47-52. doi: 10.1089/thy.2007.0351.
Nonionic polymers such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), and dextran amplify the ability of thyroid stimulating antibodies (TSAbs) from patients with Graves' disease to stimulate cAMP production in thyroid cells. Therefore we sought to determine if nonionic polymers also augment the effects of the human thyroid stimulating monoclonal antibody (M22) on isolated thyroid cells.
The ability of nonionic polymers to alter the effects of M22 on certain parameters in porcine thyroid cells was examined. These parameters were augmentation of cAMP production (TSAb activity), inhibition of bovine thyrotropin (bTSH)-induced cAMP production (TBAb activity), and inhibition of bTSH binding to the TSH receptor (TSHR) (TBI activity).
Stimulation of cAMP production by M22 in porcine thyroid cells was augmented by PEG, PVA, and dextran in a manner similar to that of Graves' serum. In contrast, TSH-stimulated cAMP production was not increased by nonionic polymers. M22-stimulated cAMP production was completely inhibited by the sera of patients with TBAb activity, and this inhibition was diminished by PEG. M22 and TBI activity in first and second generation assays and this activity was not affected by PEG. Binding of biotin-M22 to TSHR-coated plate wells (third generation assay) was not significantly increased by co-incubation with polymers. PEG augmented the binding of (125)I-M22 to TSHR-coated tubes by twofold, but this was associated with a threefold increase in nonspecific binding. There was no increase in total and nonspecific (125)I-TSH binding. This means that PEG has less than a twofold augmentative effect on (125)I-M22 binding to the TSHR.
Nonionic polymers have similar effects in augmenting cAMP production in porcine thyroid cells in response to stimulation either by M22 or Graves' disease serum. The mechanism of this effect on the thyroid stimulating activity of M22 is unclear. The hypothesis that nonionic polymers augment M22 thyroid stimulation by increasing the mass of M22-occupied TSH receptors is not supported by the present study.
非离子聚合物，如聚乙二醇（PEG）、聚乙烯醇（PVA）和右旋糖酐，可增强格雷夫斯病患者的促甲状腺素抗体（TSAbs）刺激甲状腺细胞中cAMP生成的能力。因此，我们试图确定非离子聚合物是否也能增强人促甲状腺素单克隆抗体（M22）对分离的甲状腺细胞的作用。
检测非离子聚合物改变M22对猪甲状腺细胞某些参数影响的能力。这些参数包括cAMP生成的增强（TSAb活性）、牛促甲状腺素（bTSH）诱导的cAMP生成的抑制（TBAb活性）以及bTSH与促甲状腺素受体（TSHR）结合的抑制（TBI活性）。
PEG、PVA和右旋糖酐以与格雷夫斯病血清类似的方式增强了M22对猪甲状腺细胞中cAMP生成的刺激作用。相比之下，非离子聚合物并未增加TSH刺激的cAMP生成。M22刺激的cAMP生成被具有TBAb活性患者的血清完全抑制，而PEG可减轻这种抑制。第一代和第二代检测中的M22和TBI活性不受PEG影响。与聚合物共同孵育并未显著增加生物素-M22与TSHR包被板孔的结合（第三代检测）。PEG使（125）I-M22与TSHR包被管的结合增加了两倍，但这伴随着非特异性结合增加了三倍。（125）I-TSH的总结合和非特异性结合均未增加。这意味着PEG对（125）I-M22与TSHR结合的增强作用小于两倍。
非离子聚合物在增强猪甲状腺细胞对M22或格雷夫斯病血清刺激的cAMP生成方面具有相似作用。这种对M22促甲状腺活性的作用机制尚不清楚。本研究不支持非离子聚合物通过增加M22占据的TSH受体数量来增强M22甲状腺刺激作用的假说。
