Study On The Regulation Of Sodium Iodide Symporter By Cytokines In Thyroid Gland And Development And Utilization Of Monoclonal Antibody Against Human Sodium Iodide Symporter

Objective (1) To develop monoclonal antibody against human sodium iodide symporter and investigate the expression of NIS antigen on various thyroid tissues. (2) To study the influence of cytokines on sodium iodide symporter (NIS) mRNA expression in thyroid cells. Methods (1) The hybridoma cell lines were obtained by fusing spleen cells of BALB/C mice that had been immunized with synthesized NIS peptides. The monoclonal antibody was characterized by ELISA Western-blot and immunohistochemical staining. (2) Immunostaining of various thyroid tissues was performed with the monoclonal antibodies. (3) Thyrocytes from patients with Graves disease (GD) were cultured in the absence or presence of different concentrations of tumor necrosis factor (TNF- α ), interleukin-6 (IL-6) and interferon-y (IFN- γ ) for 48h. The level of NIS gene expression was assessed by reverse transcription polymerase chain reaction (RT-PCR). Results (1)2 hybridoma cell lines were developed. These cell lines could stably secrete monoclonal antibody which could react specifically with synthesized NIS peptides. The result ofWestern-blot showed that the monoclonal antibody could recognize molecules of relative molecular mass 97KD in the target cells. (2) The immunostaining with monoclonal antibody against hNIS was specific for the follicular epithelium and concentrated at the basolateral portion of the follicularcell membrane. Various thyroid tissues showed different density of immunostaining. (3) TNF- α , IL-6 and IFN- γ inhibited NIS mRNA on thyroid cells in a dose-dependent manner. Conclusions Monoclonal antibody against human sodium iodide symporter has been developed and utilized successfully. Cytokines such as TNF- α , IL-6 and IFN- γ play important roles in the regulation of thyroid function and in the pathogenesis of thyroid homeostasis.