中文摘要：

肿瘤坏死因子alpha的拮抗剂是治疗多种炎症性自身免疫疾病的首选，但抗体类拮抗物因副作用明显而使用受限，尤其是机体内抗抗体的产生，严重影响治疗效果和药物代谢。而肽类物除免疫原性低之外，和小分子相比也有更低的毒性和更强的靶标特异性。使用7肽和12肽两种M13噬菌体展示库筛选TNFα拮抗肽，以分析7肽和12肽分别作为TNFα拮抗肽的亲和性与功能性。经过3～4轮的筛选和验证，得到2条7肽序列和2条12肽序列。利用ELISA方法检测合成肽与TNFα结合的亲和性，编号632的7肽亲和性最强，Kd=138nmol／L；编号636的12肽亲和性稍差，Kd=8．59μmol／L。InsightⅡ软件分别分析632肽和636肽与TNFα二聚体结合，发现632肽与TNFα二聚体结合更加稳定，并且在细胞水平上632肽拮抗TNFα活性功能比636肽更强，有632肽存在的条件下TNFα诱导的L929细胞生存率上升了3倍，而636肽的作用只有2倍。7肽比12肽更适合作为TNFα拮抗肽。

英文摘要：

The antagonist of tumor necrosis factor alpha is the first choice for the treatment of multiple inflammatory autoimmune diseases. Treatment with TNFα antibodies is restricted by their side effects, particularly, the production of anti- antibodies, which seriously affect the treatment efficacy and drug metabolism. Short peptides have low immunogenicity, and compared to small molecules, they also have lower toxicity and stronger target specificity. Using M13 based 7-met and 12-mer peptides phage display libraries to screen TNFα binding peptide ligands, and analyzed the affinity and functionality of the selected TNFα antagonist. After 34 rounds of screening, two 7-mer and two 12-mer peptide sequences were obtained. Binding affinity of the synthetic peptides for TNFα was determined by ELISA. 7-met peptide with number 632 showed affinity of Kd = 138nmol/L, while the 12-met peptide with number 636 showed lower affinity of Kd = 8.59μmol/L. Insight II software was used to carry out Zdock with TNFα dimer, and it was found that both the 7-mer peptide could bind to TNFα with a more stable state than the 12-mer peptide. At the cellular level, the peptide 632 were more resistant to the activity of TNFα than peptide 636. In the presence of peptide 632, the survival rate of L929 cells induced by TNFα was 3 times higher, hut the 636 peptides were only 2 times. Altogether, the 7-mer peptides were more suitable than 12-mer peptide as TNFα antagonist.