以调节性T细胞为作用靶点的细菌溶解产物对变应性鼻炎的免疫调控作用

Allergic rhinitis (AR) is characterized by Th2-skewed hyperresponsiveness. Most of the current treatments are to target the symptoms. Immunotherapy also has some limitations. Regulatory T cells can inhibit TH2 response and should be the new target to inhibit the allergic inflammation. However, the reports about frequencies of Treg cells in AR patients are insistent mainly because of the phenotypic ambiguity. It was reported that Broncho-Vaxom (BV) could inhibit the AR inflammation in the animal models. However, it was not satisfied for the clinical trials. It may be because of the unclear treatments and unclear mechanism of BV on allergic airway. We previously found that it is insufficient for the rest and active Treg in AR patients. We further found that BV prevents the allergic inflammation in a mouse model of AR and asthma. Therefore, we hypothesize that BV could inhibit the allergic inflammation via upregulating Treg. In this project, we aim (1) to investigate the Treg subtypes in AR patients; (2) to investigate the effects of BV on the subtypes of T cells; (3) to study the effects of BV on the allergic inflammation using acute and chronic AR and asthma model in mice, to examine the effects on T cells and dendritic cells, and examine whether BV plays the above effects via regulating Treg functions. This project could provide a new therapy to AR and will provide the useful information for the clinical trials of BV.

变应性鼻炎（AR）是以TH2为主导的慢性炎症，临床多对症治疗，免疫治疗的疗效不满意。调节性T细胞（Treg）可有效控制TH2反应，当是防治AR的新靶点。但因之前对其表型定义不清以致AR中Treg细胞是否存在缺陷报道不一。细菌溶解产物（BV）可调节免疫反应，但其对变应性炎症的作用、方式及调节机理等探讨不足。我们前期发现AR患者静息及活化Treg均存在缺陷；BV可有效控制急性AR、哮喘小鼠鼻及肺部炎症浸润，降低TH2反应。由此我们设想BV可通过调节Treg细胞而调控AR炎症；拟进一步探讨AR患者Treg亚群表达；体外观察BV对T细胞各亚群的调节作用；应用急性、慢性AR及哮喘小鼠模型观察不同BV处理对AR炎症、组织重塑的控制作用及对T细胞各亚型 、树突状细胞的作用；探讨其是否通过上调Treg而发挥上述作用的。本课题可为AR治疗提供新的方案，并可为BV迅速、合理地向临床应用转化提供坚实的理论依据。

变应性鼻炎（AR）是以TH2 为主导的慢性炎症，目前多采用对症治疗，免疫治疗具有局限性。调节性T 细胞（Treg）可有效控制TH2 反应，是AR免疫治疗的新靶点。细菌溶解产物（BV）可通过影响调节性T细胞发挥免疫平衡的作用，对于变应性鼻炎乃至变应性气道疾病是有效的免疫治疗方法。在国家自然科学基金的支持下，我们成功建立了变应性气道炎症高反应性动物模型并且运用细菌溶解产物对动物模型进行干预，发现细菌溶解产物能改善小鼠喷嚏、挠鼻等临床模拟症状，降低血清中OVA特异性IgE的水平，减少鼻腔粘膜下及气管周围炎症细胞特别是嗜酸性粒细胞的浸润，降低肺泡灌洗液及鼻腔灌洗液中炎症细胞的总量及嗜酸性粒细胞的数量，降低了肺泡灌洗液及鼻腔灌洗液中Th2型细胞因子的表达，扭转了变应性气道高反应性炎症中的Th1/Th2平衡失调和增加调节性T细胞（Treg）的重要转录因子Foxp3的表达及Treg相关细胞因子的表达。机制研究发现细菌溶解产物是通过影响糖原合成酶GSK-3β的表达增高进而增加Treg细胞的数量和Treg细胞重要转录因子Foxp3的表达来实现对呼吸道变应性炎症进行良性干预。进一步我们发现活化型Treg细胞在AR患者外周血和局部鼻黏膜炎性组织中存在缺陷。其表面特异性高表达趋化因子受体CCR4，趋化实验证实活化型调节性T细胞可以在CCR4趋化因子受体所对应的趋化因子CCL17/CCL22的作用下发生趋化，并可以被CCR4受体的拮抗剂和CCL17/CCL22的中和蛋白所阻断。动物结果显示趋化蛋白CCL17/CCL22可以通过趋化活化型调节性T细胞到达气道变应性炎症的局部产生抑制变应性炎症和恢复免疫平衡的作用。而采用CCR4的阻断剂和CCL17/CCL22的中和蛋白的动物实验组并没有明显的改善，故CCL17/CCL22-CCR4-aTreg这一作用通路对于气道变应性炎症的改善至关重要。本面上项目课题的相关实验研究将为细菌溶解产物治疗上下呼吸道变应性疾病提供可靠的实验依据及可行的临床研究方案，同时也探究调节性T细胞在变应性疾病中的作用机制和作用靶点，为将来较快的实现临床应用提供了实验依据，符合当前转化医学的理念。