IL-2Rα模拟肽的筛选及其抑制小鼠皮肤移植排斥反应的研究

发布时间：2018-06-22 03:27

本文选题：噬菌体展示 + IL-2Rα　；参考：《吉林大学》2007年博士论文

【摘要】： 免疫抑制剂在器官移植排斥反应的预防和治疗中起到了关键作用,人们认为最佳的免疫抑制剂至少应达到三个目标:选择性、协同性和特异性。但是,当前临床应用的免疫抑制剂只是部分地满足这些目标。为研制新型的肽类免疫抑制剂,我们以抗人IL-2Rα单克隆抗体5G1为靶分子,对噬菌体环七肽库进行了5轮筛选,经鉴定获得了5个与靶分子具有高亲和力的噬菌体阳性克隆,通过对其DNA序列进行分析,得到IL-2Rα模拟表位肽的氨基酸保守序列: Lys-X-{X}-Lys-Gly。应用化学合成法制备环七肽CP,其氨基酸序列为:Cys-Asn-Ala-Leu- Lys-Arg-Lys-Gly-Cys,相对分子量为990.2。经检测证实CP对正常小鼠脾细胞没有毒性。计算机模拟证实CP与人IL-2的功能活性部位可形成稳定、良好的结合。经淋巴细胞周期测定、淋巴细胞增殖反应、迟发型超敏反应和局部移植物抗宿主反应等多项体内外的实验证实:环七肽CP具有较强的免疫抑制活性,其与环孢菌素A联用抑制效应明显增强,显示二者具有协同效应。环七肽CP可有效地抑制小鼠异基因皮肤移植排斥反应,诱导出宿主对皮肤移植物的耐受;实验证实克隆不应答、减少宿主体内CD4+ T淋巴细胞的数目和抑制其功能、Th1型细胞因子偏移的纠正等机制参与了移植耐受的形成。以上的实验结果表明:环七肽CP以IL-2Rα模拟肽的方式发挥生物学效应,本研究为将其研制成一种高效、低毒、特异性强的小分子肽类免疫抑制剂奠定了基础。
[Abstract]:Immunosuppressants play a key role in the prevention and treatment of organ transplantation rejection. It is considered that the best immunosuppressant should achieve at least three goals: selectivity, synergy and specificity. However, the current clinical use of immunosuppressants only partially meets these goals. In order to develop a novel peptide immunosuppressant, we used 5G1 monoclonal antibody against human IL-2R 伪 as target molecule to screen phage cyclopeptide library for five rounds. Five phage positive clones with high affinity to target molecule were obtained. The amino acid conserved sequence of IL-2R 伪 mimic epitope peptide was obtained by analyzing its DNA sequence: Lys-X- {X} -Lys-Gly. The cyclic heptapeptide CPS was prepared by chemical synthesis. Its amino acid sequence was: 1 Cys-Asn-Ala-Leu-Lys-Arg-Lys-Gly-Cys-Gly-Cys. the relative molecular weight was 990.2. CP is not toxic to spleen cells of normal mice. It was proved by computer simulation that the functional active sites of CP and IL-2 could form stable and good binding. Lymphocyte cycle assay, lymphocyte proliferation, delayed type hypersensitivity and local graft versus host reaction in vivo and in vitro confirmed that cyclopeptide CP had strong immunosuppressive activity. The inhibitory effect of cyclosporine A combined with cyclosporine A was significantly enhanced, indicating that the two had synergistic effect. Cyclopeptide CP can effectively inhibit allogeneic skin graft rejection in mice and induce host tolerance to skin grafts. The mechanism of decreasing the number of CD4 T lymphocytes and inhibiting the correction of Th1 type cytokine shift in host is involved in the formation of transplantation tolerance. The above results show that cyclic heptapeptide CP exerts biological effect on IL-2R 伪 mimic peptide. This study has laid a foundation for the development of a small molecular peptide immunosuppressant with high efficiency, low toxicity and strong specificity.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2007
【分类号】：R392.33

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