Chiovato L, Vitti P, Lombardi A, Kohn L D, Pinchera A
J Clin Endocrinol Metab. 1985 Jul;61(1):12-6. doi: 10.1210/jcem-61-1-12.
The thyroid microsomal antigen, commonly implicated in thyroid autoimmune diseases, is not confined to cytoplasm, but is also present on the surface of human thyroid cells in primary culture. In this study, a strain of differentiated rat thyroid cells (FRTL5) grown in continuous culture was used to investigate the relationship between functional status of the thyroid cell and expression of microsomal antigen on its surface. Sera from eight patients with Hashimoto's thyroiditis, one with idiopathic hypothyroidism, and three with hyperthyroid Graves' disease were selected for the presence of microsomal antibody, but undetectable thyroglobulin antibody. One additional serum sample from a patient with Graves' disease, which was negative for both thyroid antibodies was used. Sera from eight normal subjects were used as controls. Indirect immunofluorescence was applied to FRTL5 cells that were viable or fixed with acetone in order to expose intracellular antigens. When FRTL5 cells were cultured in Coon's medium containing TSH (300 microU/ml), positive indirect immunofluorescence surface staining was observed with sera containing microsomal antibody, but not with control sera or with the Graves' serum negative for microsomal antibody. A rough correlation was found between the intensity of the surface fluorescence and microsomal antibody titer. After acetone treatment, microsomal antibody-positive sera produced typical cytoplasmic staining. When FRTL5 cells were cultured in the absence of TSH, disappearance of the surface fluorescence and reduction of the cytoplasmic microsomal antigen occurred. Readdition of TSH progressively restored both the surface and cytoplasmic microsomal antigen. The present data indicate that the thyroid microsomal antigen is represented on the surface of FRTL5 cells, and its expression is modulated by TSH.
甲状腺微粒体抗原通常与甲状腺自身免疫性疾病有关，它不仅局限于细胞质中，在原代培养的人甲状腺细胞表面也有存在。在本研究中，使用连续培养的分化大鼠甲状腺细胞系（FRTL5）来研究甲状腺细胞的功能状态与其表面微粒体抗原表达之间的关系。选取了8例桥本甲状腺炎患者、1例特发性甲状腺功能减退患者和3例甲状腺功能亢进的格雷夫斯病患者的血清，检测其中是否存在微粒体抗体，但未检测到甲状腺球蛋白抗体。另外还使用了1例格雷夫斯病患者的血清样本，该样本的两种甲状腺抗体均为阴性。8例正常受试者的血清用作对照。将间接免疫荧光法应用于活的或用丙酮固定的FRTL5细胞，以暴露细胞内抗原。当FRTL5细胞在含促甲状腺激素（300微单位/毫升）的库恩培养基中培养时，含有微粒体抗体的血清可观察到阳性间接免疫荧光表面染色，而对照血清或微粒体抗体阴性的格雷夫斯病血清则未观察到。表面荧光强度与微粒体抗体滴度之间存在大致的相关性。丙酮处理后，微粒体抗体阳性血清产生典型的细胞质染色。当FRTL5细胞在无促甲状腺激素的情况下培养时，表面荧光消失，细胞质微粒体抗原减少。重新添加促甲状腺激素可逐渐恢复表面和细胞质微粒体抗原。目前的数据表明，甲状腺微粒体抗原存在于FRTL5细胞表面，其表达受促甲状腺激素调节。
