噬菌体展示肽功能化糖原精准递送CpG ODN逆转Th1/Th2免疫应答失衡治疗花粉症的研究

In recent years, the incidence of pollinosis has risen rapidly, which is a serious threat to human health. The traditional "symptomatic" treatment can only alleviate the symptoms but cannot completely cure the pollen allergy. Based on the pathogenesis of pollinosis and from the perspective of immunotherapy, this study aims to construct a precise immunomodulator CpG ODN delivery system in order to reverse the imbalance of Th1/Th2 immune response and to achieve the goal of effective treatment of pollinosis. We will use phage display technique to screen peptide with targeting ability to DC cells. Then we will use peptide-functionalized glycogen as carrier for the delivery of CpG ODN. The DC cells-targeting peptide is expected to promote the endocytosis of the carrier and thereby increase the CpG ODN uptake. Glycogen can activate DC cells and can be hydrolyzed by glycosidase in lysosomes to release CpG ODN, which will further enhance the interaction of CpG ODN with TLR9. The efficiency of the delivery system and its therapeutic effect on pollinosis will be verified by cell and animal experiments. The mechanism of action of the precise delivery system against pollen allergy will be revealed by analyzing the levels of the representative cytokines and antibodies for Th1 and Th2 type immune response. This study is a new development in the construction and application of CpG ODN delivery system, which is innovative. This work will provide new ideas and theoretical basis for the innovation of pollinosis treatment drugs and clinical treatment of pollinosis.

近年来，花粉症的发病率迅速上升，严重影响人类健康。传统的“对症”治疗方式只能缓解症状，无法从根本上治愈花粉过敏。本研究基于花粉症发病机制，从免疫治疗思路出发，利用噬菌体展示技术筛选靶向DC细胞多肽，旨在构建以糖原为载体，能够精准递送免疫调节剂CpG ODN至DC细胞溶酶体与TLR9作用的递送系统，以期逆转Th1/Th2免疫应答失衡，达到高效治疗花粉症的目的。靶向肽有望促进载体被DC细胞内吞进而提高CpG ODN摄取率。糖原可活化DC细胞，并可在溶酶体内被糖苷酶水解释放出CpG ODN与TLR9作用。通过细胞实验和构建花粉症小鼠模型验证递送系统的效率以及对花粉症的治疗效果。通过分析Th1和Th2型代表性细胞因子、抗体水平揭示精准递送系统抑制花粉过敏的作用机制。本研究是CpG ODN递送系统构建、应用方面的新发展，具有创新性。本项目将为花粉症治疗药物的创新和临床治疗提供新思路和理论依据。

传统的花粉症治疗方法主要是“对症”治疗，采用糖皮质激素、抗组胺药物等控制、缓解过敏反应所致炎症，无法从根本上治愈花粉过敏。这些治疗方法也伴随中枢神经抑制等不良反应。针对传统花粉症治疗方法的不足，本项目从免疫治疗思路出发，利用噬菌体展示技术筛选到了一个靶向DC细胞的多肽，随后用此靶向多肽修饰糖原纳米粒子，构建了CpG ODNs的精准递送系统PG-CpG NPs。实验结果表明，PG NPs具有较好的细胞和血液相容性，能够有效包载CpG ODNs并保护其免受核酸酶分解；DC细胞靶向多肽能够促进载体被DC细胞内吞，进而显著提高CpG ODNs摄取率；PG-CpG NPs能够活化BMDCs并可在溶酶体内被α-葡萄糖苷酶水解释放出CpG ODN与TLR9作用； PG-CpG NPs能够显著提高Th1型免疫应答，抑制Th2型免疫应答，进而逆转Th1/Th2免疫应答失衡，对花粉症具有较好的治疗效果。项目的研究结果可为花粉症治疗药物的创新和临床治疗提供新思路和理论依据，具有重要的意义和广阔的应用前景。

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