牛虻唾液腺中一种新型免疫抑制肽结构，功能及作用机制研究

Horsefly is widely used in traditional Chinese medicine. As a blood-sucking arthropods, horsefly has developed many immunoregulator compounds in salivary gland in order to withstand the host immune response and suck blood successfully from the host after the lone-term evolution period. We purified a new immunosuppressive peptide named immunoregulin HA from the salivary gland extract of Hybomitra atriperoides. It is composed of 30 amino acid residues. Immunoregulin HA possibly upregulates the IL-10 production to inhibit inflammatory cytokines IFN-γ and MCP-1 secretion. In our next work, we will firstly focus on the stucture and the key amino acide sites of the immunosupressive HA. Secondly, We will try to find out its regulation on different immune cells in cell proliferation, apoptosis, differentiation and the possible mechanisms at both molecular level and cell level. Finally, we will use animal models to evaluate immunosuppressive peptide immunoregulin HA's activity in vivo, thus to make it possible to reform and design newly immunosuppressive molecules in future.

牛虻（虻虫）是我国重要的中药材，牛虻唾液腺在长期的进化过程中形成免疫调节因子以逃避宿主免疫反应，从而保证成功地从宿主获得血液。我们从拟黑腹牛虻的唾液腺中分离纯化得到一种新型的含有30个氨基酸残基的免疫抑制肽immunoregulin HA。前期工作表明immunoregulin HA可能是通过上调IL-10的产生来抑制炎症因子IFN-γ和MCP-1的分泌。本课题首先将研究免疫抑制肽immunoregulin HA可能的结构及关键氨基酸位点。其次从分子水平、细胞水平深入研究抑制肽immunoregulin HA对几类免疫细胞的增殖、凋亡、分化的调控及可能的作用机制。最后利用动物模型评估免疫抑制肽immunoregulin HA的体内活性，为改造和设计新型免疫抑制剂分子打下基础。

在前期新发现的一种免疫抑制肽的基础上，深入研究了拟黑腹瘤虻唾液腺新型免疫抑制肽HA的作用机制，发现其对免疫效应细胞，脾细胞、巨噬细胞系R264.7、CD4+ T类群的细胞均无增殖作用。通过western-blot对巨噬细胞系R264.7释放IL-10所涉及到的信号通路分析，我们发现其可能通过影响HA可能主要作用于MKK4-JNK进而影响细胞核内相关细胞因子的转录因子激活，并对CD4+ T 细胞类群中Th1/Th2的平衡产生影响。通过荧光定量PCR检测相关信号途径的响应值也能很好的证明，HA可能主要作用于MKK4-JNK途径。分析HA处理后的小鼠血象，发现HA对单核细胞有特异性的作用。通过弗氏佐剂诱导的小鼠足底炎症抑制模型可以看出，多肽HA有较好的体内抑制炎症的功能，且溶血活性极低，上述实验证实多肽HA有较好的开发应用前景，或可开发成为一种新型的多肽类免疫抑制剂。