胰岛素样生长因子-1促进应激小鼠T淋巴细胞分泌细胞因子的机制研究

We found that the stressed mice antigen-specific T lymphocytes cultured with IGF-1 can enhance autocrine of IL-2 derived from T cells. Now know that secretion of IL-2 derived from T cells in immune response firstly depends on T cell activation induced by the second signal. Recent researches have shown that there is a significant interaction between integrinβ, an important role in the formation of second signal to induce T cells activation, and IGF-1 in signaling pathways mediating cell proliferation, in which integrin signaling pathways is also regulated by the IGF-1 while integrin regulates the IGF-1 signaling pathways, but it is not clear whether IGF-1 promotes the secretion of IL-2 of T cells via integrin. We presume that IGF-1 may be involved in the formation of second signal for T lymphocyte activation or promotes the secretion of IL-2 under the direct regulation of integrin by the form of the integrin-IGF-1-IGF-1R complex. We intend to establish a model of T cell immune response in vivo and in vitro, analyse the relationship between integrin, IGF-1 and IGF-1R with co-immunoprecipitation, immunoblotting, real-time fluorescent quantitative-PCR, etc., and then, prove the speculation in this project from three aspects of the component factors of second activation signal, the formation of the ternary complex and the IL-2 secreted by T cell. These experiments will provide a new clue to further study the immune response mechanism and treat stress in clinic.

我们观察到应激小鼠抗原特异的T淋巴细胞体外培养时给予IGF-1能增强其分泌IL-2，目前所知免疫应答中T细胞分泌IL-2与否取决于T细胞能否先被第二活化信号激活。最近发现在第二活化信号中有重要作用的整合素与细胞增殖中的IGF-1信号通路有交互作用，整合素调节IGF-1信号通路同时IGF-1也调节整合素通路，但不清楚IGF-1是否通过整合素促进T细胞分泌IL-2。我们推测IGF-1可能以"整合素-IGF-1-IGF-1R"三元体形式参与了T细胞第二活化信号的形成或直接在整合素调控下促进IL-2分泌。本课题拟建立体内、外T细胞免疫应答，应用免疫共沉淀、免疫印迹、实时荧光定量-PCR等分析整合素β、IGF-1、IGF-1R之间的关系，从第二活化信号成因、三元体构成和T细胞分泌IL-2三个层面证明课题的推测。本实验将为进一步研究免疫应答机制和临床治疗应激提供一条新线索。

课题旨在研究IGF-1在抗原特异的T淋巴细胞第二活化信号形成中可能担当的角色，即IGF-1信号转导通路在免疫应答中可能起的作用。我们采用实时荧光定量-PCR、Westerm blot等方法动态检测免疫应答中的抗原提呈细胞（APC）、T细胞的整合素-βmRNA和T细胞的IGF-1RmRNA、IGF-1mRNA表达情况，并用IGF-1单抗、IGF-1受体拮抗剂（IGF-1Ra）和整合素-β3抑制物作阻断试验，分析整合素-β、IGF-1、IGF-1R三者间的关系是否符合我们设想的“整合素–IGF-1–IGF-1R”三元体结构。实验结果表明IGF-1在免疫应答中对T细胞第二信号形成发挥了信号转导作用，并且与整合素-β3、IGF-1R一起完成APC与T细胞之间的信号转导作用, 本实验将为进一步研究免疫应答机制和临床治疗应激提供一条新线索。接下来，只要我们能够继续确认阻断试验的效果具有与Daniel Bilbao 等人报道的Treg细胞IGF-1R基因敲除法的效果那样高度可信，则我们有充分理由认为IGF-1在免疫应答的信号转导中是以“整合素–IGF-1–IGF-1R”三元复合体存在形式去发挥作用的, 并意味着T细胞膜上的“integrin—IGF-1—IGF-1R”三元体形态构想也将成立。.