Therapeutic treatment of EAT by inducing dendritic cell

实验性自身免疫性甲状腺炎(EAT)的特征是浸润性甲状腺最终破坏。 导致甲状腺功能减退的淋巴细胞。产生干扰素-γ、肿瘤坏死因子-α和白介素12的CD4+T细胞 对发病机制至关重要。在最近的一项研究中，我们发现相对于甲状腺球蛋白(MTG)的免疫 对照组，用Flt3-L治疗的小鼠出现了更严重的EAT，其特征是甲状腺肿大 淋巴细胞浸润和IL-2、干扰素-γ的产生。相比之下，GM-CSF治疗的小鼠未能 发展为EAT，并表现出明显增加的CD4+CD25+调节性T细胞(Tregs)。激活 这些带有MTG的小鼠的淋巴细胞在体外产生更高水平的IL-4和IL-10。中和IL-10， 但不是IL-4，这些培养物中Tregs的耗尽恢复了MTG特异性T细胞的增殖和IL-2 和干扰素-γ的产生。此外，将Tregs过继转移到MTG免疫的小鼠可抑制EAT 而接种抗IL-10受体抗体则可逆转GM-CSF对EAT的抑制作用。这些 结果表明，抑制EAT是由Tregs介导的，很可能是通过促进 IL-10。 基于这些结果，我们假设：使用GM-CSF选择性激活CD8a-树突状细胞 可以激活CD4+CD25+调节性T细胞并使正在进行的抗甲状腺球蛋白免疫反应偏向有利 Th2型，对实验性糖尿病的发展和/或进展有抑制作用 在AIM-1中，GM-CSF对自身免疫性甲状腺炎提供长期抗原特异性保护的有效性。 将对再次暴露于MTG进行测试。在AIM-2中，我们将检测CD8a-和CD8a+DC经历 成熟，捕获和呈递抗原，产生细胞因子，并确定MTG特异性T细胞 表型和细胞因子谱。将测试DC和T细胞在体外和体外的抑制能力 WT和IL-10-/-小鼠体内MTG特异性反应。在AIM-3中，我们将测试GM-CSF、DC和 MHC和B7分子表达、ARC功能及对Fas诱导的细胞凋亡敏感性的研究 来自WT和SCID小鼠的甲状腺细胞。这些研究将对行动模式提供重要的见解 GM-CSF对EAT的抑制作用。

Experimental Autoimmune Thyroiditis (EAT) is characterized by eventual destruction of thyroid by infiltrating lymphocytes resulting in hypothyroidism. CD4+ T cells that produce IFN-gamma, TNF-alpha and IL-12 are critical for the pathogenesis. In a recent study, we showed that relative to thyroglobulin (mTg) immunized controls, mice treated with Flt3-L developed a more severe EAT characterized by massive thyroid lymphocytic infiltration, and IL-2and IFN-gamma production. In contrast, GM-CSF treated mice failed to develop EAT, and showed a significant increase in CD4+CD25+ regulatory T cells (Tregs). Activationof lymphocytes from these mice with mTg in vitro yielded higher levels of IL-4 and IL-10. Neutralization of IL-10, but not IL-4, and depletion of Tregs from these cultures restored mTg specific T cell proliferation, andIL-2 and IFN-gamma production. Further, adoptive transfer of Tregs to mTg immunized mice suppressed EAT while, inoculation of anti-IL-10 receptor Ab reversed GM-CSF induced suppression resulting in EAT. These results showed that suppression of EAT was mediated by Tregs most likely through enhanced production of IL-10. Based on these results we hypothesize that "selective activation of CD8a- dendritic cells using GM-CSF can activate CD4+CD25+ regulatory T cells and skew ongoing anti-thyroglobulin immune responses in favor of Th2 type, with consequent suppressive effects on the development and/or,progression of experimental autoimmune thyroiditis." In Aim-1, efficacy of GM-CSF to confer long-term antigen specific protection upon re-exposure to mTg will be tested. In Aim-2, we will test the ability of CD8a- and CD8a+ DCs to undergo maturation, capture and present the antigen, and produce cytokines, and determine the mTg specific T cell phenotype and cytokine profiles. Both DCs and T cells will be tested for their ability suppress in vitro and in vivo mTg specific responses in WT and IL-10-/- mice. In Aim-3, we will test the effects of GM-CSF, DCs and Tregs on the expression of MHC and B7 molecules, ARC function, and sensitivity to Fas induced apoptosis of thyrocytes from WT and SCID mice. These studies will provide significant insights into the mode of action of GM-CSF in suppressing EAT.