de Forteza R, Smith C U, Amin J, McKenzie J M, Zakarija M
Department of Medicine, University of Miami School of Medicine, Florida 33101.
J Clin Endocrinol Metab. 1994 May;78(5):1271-3. doi: 10.1210/jcem.78.5.7909819.
In autoimmune thyroid disease there are various autoantibodies (Ab) to thyroid cell components. Among the best characterized are those to thyroid peroxidase (TPOAb) and to the thyrotropin receptor (TRAb). While TPOAb were successfully used to visualize TPO in human thyroid cells (HTC) and a rat thyroid cell line (FRTL5) by indirect immunofluorescence (IFL), similar attempts with TRAb and thyrotropin receptor (TSHR) failed. This could have been due to either relatively low serum levels of TRAb and/or low number of TSHR on thyroid cells. To test these hypotheses, we estimated the number of TSH binding sites on HTC, FRTL5 and Chinese hamster ovary (CHO) cells, transfected with cloned human TSHR (JP-26 cells), and for IFL staining employed 3 sera with the highest potency TRAb in our possession. A clear granular surface staining was detected on all 3 cell types with two sera; with the third, the least potent, no staining was seen. The density of staining paralleled the estimated number of TSHR per cell, i.e., JP-26 > FRTL5 > HTC. TSHR was also visualized on transiently transfected cells (COS-7-TSHR), facilitating quantitation of transfection. Our results suggest that the limiting factor in direct visualization of the TSHR is the TRAb concentration.
在自身免疫性甲状腺疾病中，存在多种针对甲状腺细胞成分的自身抗体（Ab）。其中研究最为深入的是针对甲状腺过氧化物酶（TPOAb）和促甲状腺激素受体（TRAb）的抗体。虽然通过间接免疫荧光法（IFL）成功利用TPOAb在人甲状腺细胞（HTC）和大鼠甲状腺细胞系（FRTL5）中使TPO可视化，但针对TRAb和促甲状腺激素受体（TSHR）的类似尝试却失败了。这可能是由于TRAb的血清水平相对较低和/或甲状腺细胞上TSHR数量较少。为了验证这些假设，我们估计了HTC、FRTL5以及转染了克隆人TSHR的中国仓鼠卵巢（CHO）细胞（JP - 26细胞）上促甲状腺激素结合位点的数量，并使用了我们所拥有的效价最高的3份TRAb血清进行IFL染色。两份血清在所有3种细胞类型上均检测到清晰的颗粒状表面染色；而效价最低的第三份血清则未观察到染色。染色密度与每个细胞估计的TSHR数量平行，即JP - 26 > FRTL5 > HTC。TSHR在瞬时转染细胞（COS - 7 - TSHR）上也实现了可视化，便于对转染进行定量分析。我们的结果表明，直接可视化TSHR的限制因素是TRAb浓度。
