TLR9在宫颈癌微环境诱导的DC疫苗免疫耐受中的作用及其分子机制研究

Defect of DC function induced by tumor microenvironment play an important role in mediating immune tolerance. While TLR9 was identified recently as an important mediator of tumor-induced DC immune tolerance, the underlying mechanism remains poorly defined. The results of our previous study indicated that down regulation of TLR9 might contribute to DC immune tolerance and PD-1 might play an important role in regulatory process. To investigate the function of TLR9 and its signal transduction pathway in DC immune tolerance, in this study we will detect expression of CD83, CD86, TLR9, PD-1, PI3K、Akt of DC cells co-culturing with cervical cancer cells in transwell chambers. As an adjuvant, TLR9 will be transducted into DC vaccine. The antitumor effect of the DC vaccine will be determined. The experimental observations will elucidate the mechanism of immune tolerance of DC vaccine under cancer microenvironment. Targeting TLR9 will be a potential viable strategy to improve DC immunotherapies.

肿瘤微环境作用于DC导致其功能缺陷是肿瘤免疫耐受的重要机制之一。近年来的研究显示TLR9与DC免疫耐受密切相关，但作用机制不清。我们的前期实验结果提示宫颈癌微环境下TLR9表达下调参与了DC疫苗的免疫耐受，PD-1可能在这个过程中发挥重要的调控作用。本研究拟在此基础上，利用Transwell小室将DC疫苗与宫颈癌组织共培养，检测肿瘤微环境下DC疫苗功能分子如CD83、CD86及TLR9、PD-1、PI3K、Akt等表达的变化，以明确TLR9在DC疫苗免疫耐受中的作用及信号传导途径。然后将TLR9作为佐剂修饰DC疫苗，并验证其抗肿瘤效应。本实验结果将有助于阐明DC疫苗免疫耐受的发生机制，并为DC疫苗的改进提供新思路。

树突状细胞是目前发现的体内功能最强的专职抗原提呈细胞，能显著刺激未致敏T细胞的活化增殖，起到抗肿瘤作用。荷瘤机体中树突状细胞功能异常被认为是肿瘤逃避机体免疫监视的关键机制。然而，DC在肿瘤微环境发生免疫耐受的机制尚不清楚。本研究利用Transwell小室将DC与宫颈癌细胞共培养，检测肿瘤微环境下DC功能分子CD80、CD86、MHC等表达变化，明确了肿瘤微环境对DC功能的抑制作用。随后我们初步探讨了DC在肿瘤微环境中免疫耐受的可能的分子机制，通过全基因组芯片筛选出耐受前后DC细胞的差异表达基因，并进行验证。结果发现TRAF6可能是DC在肿瘤微环境中发生免疫耐受的关键分子，对其进一步研究将为肿瘤免疫治疗改进提供新的思路。