Therapeutic treatment of EAT by inducing dendritic cell

实验性自身免疫性甲状腺炎（EAT）的特征是通过浸润性甲状腺细胞最终破坏甲状腺。 淋巴细胞导致甲状腺功能减退。产生IFN-γ、TNF-α和IL-12的CD 4 + T细胞是 对发病机理至关重要。在最近的一项研究中，我们发现，相对于甲状腺球蛋白（mTg）免疫， 对照组中，Flt 3-L处理的小鼠发生了更严重的EAT，其特征在于巨大的甲状腺 淋巴细胞浸润和IL-2和IFN-γ产生。相比之下，GM-CSF治疗的小鼠未能 发展EAT，并显示出CD 4 + CD 25+调节性T细胞（T细胞）的显著增加。激活 来自这些具有mTg的小鼠的淋巴细胞在体外产生更高水平的IL-4和IL-10。IL-10的中和， 而IL-4则不能，从这些培养物中去除TlR可恢复mTg特异性T细胞增殖，而IL-2 和干扰素-γ的产生。此外，过继性转移Tglutamine到mTg免疫的小鼠抑制EAT 而抗IL-10受体抗体可逆转GM-CSF诱导的EAT。这些 结果表明，抑制EAT是由TGFAP介导的，最有可能是通过增加EAT的产生。 IL-10。 基于这些结果，我们假设“使用GM-CSF选择性激活CD 8a-树突状细胞”， 可以激活CD 4 + CD 25+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于 Th 2型，对实验性免疫缺陷的发展和/或进展具有抑制作用。 自身免疫性甲状腺炎“在Aim-1中，GM-CSF赋予长期抗原特异性保护的功效， 将测试再次暴露于mTg。在Aim-2中，我们将检测CD 8a-和CD 8a + DCs进行免疫调节的能力。 成熟，捕获和呈递抗原，并产生细胞因子，并确定mTg特异性T细胞 表型和细胞因子谱。将测试DC和T细胞两者的体外和体内抑制能力。 WT和IL-10-/-小鼠的体内mTg特异性应答。在Aim-3中，我们将测试GM-CSF、DC和 对MHC、B7分子表达、ARC功能及Fas诱导凋亡敏感性的影响 来自WT和SCID小鼠的甲状腺细胞。这些研究将提供重要的见解的行动模式 GM-CSF抑制EAT的作用。

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.