应用噬菌体随机肽库研究人肺癌相关抗原表位  

Identification of Human Lung Cancer-related Epitopes Using Phage-display Peptide Library

作　　者：李新元[1] 黄英武[1] 郑燕华[1] 韩瑞刚[1] 

机构地区：[1]解放军306医院实验科,北京100101

出　　处：《癌症》2001年第1期35-37,共3页Chinese Journal of Cancer

基　　金：全军九五医学科研规划青年基金(编号 98Q114)

摘　　要：目的：从噬菌体随机多肽文库中筛选肺癌相关抗原ＷＬＡ－Ａｇ１表位，深入了解抗原特性，为探索肺癌临床诊断、治疗新方法打下基础。方法：采用肺癌单克隆抗体ＷＬＡ２Ｃ４对噬菌体完全随机十五肽表达文库进行多级亲和筛选，建立与ＷＬＡ２Ｃ４具亲和力的肽库；随机挑选１２个克隆，鉴定抗体特异性；测定阳性克隆ＤＮＡ序列并进行同源性及氨基酸分析。结果：１２个克隆均为阳性克隆，ＤＮＡ序列相同，为 ５’－ＧＣＴ ＧＧＴ ＴＧＧ ＡＮ ＡＣＴ ＴＴＴ　ＣＡＴ ＣＧＴＣＧＴ ＣＡＴ ＣＡＴ ＧＡＴ ＣＧＴ ＧＴＴ ＣＴＴ－３’，其氨基酸序列为 ＡＧＷＩＴＰＨＲＲＨＨＤＲＶＬ。氨基酸分析，其中有３个胰蛋白酶酶切位点，与ＷＬＡ－Ａｇ１抗原能被胰蛋白酶消化的特性相一致。结论：应用肺癌单抗ＷＬＡ－２Ｃ４从噬菌体文库筛选出的十五肽序列可能是肺癌相关抗原ＷＬＡ－Ａｇ１的模拟表位。此方法对肿瘤相关抗原表位的筛选具有可行性。Objectives: The current study was designed to identify mimic polypeptide epitopes of lung cancer-related antigen WLA-Ag1 through screening random peptide library which was on display in phages, and provide useful information for further study of the characterization of WLA-Ag1 antigen and the potential chance for developing new diagnostic or therapeutic methods for lung cancer. Methods: Through affinity enrichment and immunoscreening of phage-displayed fifteen-peptide libraries with a monoclonal antibody named WLA2C4 against WLA-Ag1, the enriched phages was obtained and plated on agar plates. Some positive clones picked at random were confirmed by ELISA using WLA2C4 monoclonal antibody and DNA sequencing. The homologous comparison of amino acid sequences of positive clones was conducted through searching the protein sequence databank on Internet. The digestion analyses of amino acid sequences were also conducted by a software. Results: Twelve positive clones have been found with a consensual DNA sequence, that is,5'- GCT GGT TGG ATT ACT TTT CAT CGT CGT CAT CAT GAT CGT GTT CTT-3'. Amino acid sequence was AGWITPHRRHHDRVL, with three trypsinase - digestible sites. This coincided with our previous finding that WLA -Ag1 can be digested by trypsinase. Conclusions: The amino acid sequence found in this study might be the epitope of WLA-Ag1. Screening of bioactive peptides from random peptide libraries using monoclonal antibodies as the ligands is an effective method to identify the epitopes of cancer-related antigens.

关 键 词：噬菌体 随机多肽文库 肺肿瘤 抗原 表位 

分 类 号：R734.2[医药卫生—肿瘤] R392.11[医药卫生—临床医学]