噬菌体随机肽库筛选抗志贺样毒素Ⅱ结合亚单位Stx2B的单抗的识别表位

目的利用噬菌体随机肽库技术筛选志贺样毒素Ⅱ结合亚单位Stx2B的单抗的识别表位。方法以抗志贺样毒素Ⅱ结合亚单位Stx2B的单克隆抗体筛选噬菌体随机12肽库，挑取阳性克隆测定DNA序列，推导其氨基酸序列并进行同源性分析。通过ELISA鉴定获得的噬菌体短肽与单抗之间的结合特性。结果从噬菌体随机12肽库中筛选出20株可与抗志贺样毒素Ⅱ结合亚单位Stx2B的单抗特异结合的噬菌体克隆，其中多数克隆呈现核心序列WTSRW（Q），该序列与志贺样毒素Ⅱ结合亚单位Stx2B的一级序列具有一定的同源性。结论WTSRW（Q）序列是志贺样毒素Ⅱ结合亚单位Stx2B单抗的识别表位。

Selection of antigenic determinants recognized by monoclonal antibody against Shiga like toxin 2B from a 12-mer random peptide library

Objective To identify the epiope of monoelonal antibody against Shiga like toxin 2B （Stx2B）. Methotis Monoelonal antibody against Stx2B was used to screen a 12-mer random pepfide library. Positive clones were obtains by three rounds of biopanning,and the reactivity of each clone binding to the monoclonal antibody was examined by sandwieh ELISA. The insert DNA sequences of positive clones were determined and their amino acid sequences were deduced. Results 20 phage clones from the third round were randomly selected, and 18 clones of them could bind to the monoelonal antibody. Analysis of DNA and amino acid sequences indicated that most selected peptides showed a sequence motif WTSRW（Q） which showed high homogeneity to the primary sequence of Stx2B amino acid. Conclusion WTSRW（Q） was antigenic determinants of Stx2B.