Inhibitory effects of thyroxine on cytokine production by T cells in mice.
As a sensitive factor of endocrine system, thyroxine exerts regulatory activities on a variety of cell types in immune system including T lymphocytes. Cytokines secreted by T lymphocytes are widely involved in numerous mechanisms, which are crucial for homeostasis at various statuses. Here we investigated the effects of thyroxine on the cytokine production of T lymphocytes in vivo and in vitro, using BALB/c mice with thyroxine treatment. We examined the IFN-gamma, IL-2, IL-4 and IL-10 of T-cell type cytokines transcriptions and the proportions of IFN-gamma, IL-4 and IL-10-secreting CD4(+)/CD8(+) T cells. The results showed that the administration of high-level thyroxine induced weakly expression of T-cell type cytokine in transcriptional level together with impaired responsibility to mitogen (Con A) stimulation. Along with the severe suppression on T-cell type cytokine transcription, the proportions of IFN-gamma, IL-4 and IL-10-producing T lymphocytes were markedly attenuated and the productions of serum IFN-gamma and IL-10 were significantly decreased synchronously. The repressive effects of thyroxine on T-cell type cytokine were seen both in mRNA and protein level. The results suggested that T lymphocytes under normal condition appear to be sensitive to suppression of high-level thyroxine administration.
Yao
Chengfang
C
Institute of Immunopharmacology & Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua Western Road, Jinan 250012, People's Republic of China. yaochengfang@yahoo.com.cn
Zhang
Jian
J
Wang
Li
L
Guo
Yuqi
Y
Tian
Zhigang
Z
D000818:Animals; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D013974:Thyroxine / Q000494:pharmacology*
D016207:Cytokines; D007376:Interleukin-2; D003208:Concanavalin A; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma; D013974:Thyroxine