利用大肠杆菌鞭毛展示的随机肽库筛选TNF—α拮抗须

TNF－α是一种在机体抗感染，抗肿瘤过程中发挥重要作用的细胞因子，其对机体具有保护和损伤两方面的作用，为了探讨新的抑制TNF－α所致炎症损伤等反应的手段，构建了细菌鞭毛递呈的随机肽库，利用构建得到的肽库，进行TNF－α特异性结合肽的筛选工作。经过5轮筛选及DNA测序，共得到6条小肽编码序列。其中2条序列中含有－V－－N－WG的相同序列框架。进行6条序列与TNF－α结合力的确证后，选择了其中的4条肽序列进行人工化学合成，纯化及鉴定。利用L929细胞及MTT法对4条小肽进行活性测定，检测其对TNF－α的抑制活性。结果表明，在TNF－α对L929细胞毒性为30％左右，含同源序列框架的2条肽可抑制90％左右的TNF－α活性。

Screening of TNF-alpha antagonist peptides from a random peptide library displayed with Escherichia coli flagellar]

Tumor necrosis factor(TNF-alpha) plays an improtant role in the process of anti-infection and anti-cancer. It can both protect and make damage to the host. In order to find new way of inhibiting its host-damaging activity, An E. coli flagella displayed random peptide library was constructed and TNF-alpha antagonist peptides were screened using the peptide library. After 5 rounds of panning and DNA sequencing, six peptide sequences were obtained. Two of them(TBP2, TBP3) have the same sequence frame of V--N-WG. After primary comparation of TNF-alpha binding ability, four peptides were synthesised and purified with RP-HPLC. The activity of inhibiting TNF-alpha was detected with L929 cell and MTT method. The data show that TBP2 and TBP3 can inhibit 90% of TNF-alpha activity when TNF-alpha gives about 30% cell toxicity on L929. The two sequences have not been reported.