应用噬菌体随机肽库技术筛选幽门螺杆菌中性粒细胞激活蛋白的抗原表位

摘要

目的 筛选和鉴定幽门螺杆菌(Helicobacter pylori,Hp)中性粒细胞激活蛋白(neutrophil-activating protein,NAP)的有效抗原表位,为Hp疫苗的研制提供基础.方法 以抗NAP的单克隆抗体作为固相筛选分子,经3轮吸附-洗脱-扩增免疫,筛选噬菌体随机7肽库,随机挑选噬菌体克隆,经噬菌体酶联免疫吸附试验(ELISA)、交叉反应试验及竞争抑制试验鉴定阳性克隆,测定阳性克隆所携带DNA序列并进行计算机辅助分析.以制备的阳性噬菌体克隆短肽液免疫小鼠,免疫血清与NAP经Western blot分析,以验证NAP的模拟表位.结果 经3轮免疫筛选后挑选到45个阳性克隆,经ELISA鉴定有12个阳性克隆,测序结果显示5种表位,其中P17噬菌体展示肽FAHLATQ与NAP氨基酸序列(137～143)高度同源,位于NAP高抗原区域(118～140),免疫血清可识别NAP.结论 用噬菌体随机7肽库成功筛选到了NAP的模拟表位,为基于NAP的诊断和疫苗的研制提供了基础.%Objective To identify epitope of neutrophil-activating protein(NAP) of Helicobacter pylori(Hp).Methods Using the mouse monoclonal antibodies against NAP as selective molecular and immunoscrcening phage-display random 7-peptides library.The positive clones were sequenced and analyzed.Phage clones were chosen to immunize mice and to evaluate the potential of phagotopes as effective vaccines.Results One mimotope(FAHLATQ)showed a good match with the NAP at 140-143 AA(AHLA)and the serum of mice induced by the phage clone clearly recognized NAP.Conclusion This study suggests thatthe antigenic epitope could be mapped through screening the phage-display peptide library with monoclonalantibody and a mimotopo of NAP providing an ahernative approach for the diagnosis and development of avaccine for Hp.