Antibody phage display technology plays an important role in the development of monoclonal antibodies, humanization, and affinity evolution of antibodies. Thus far, antibody phage display mainly focuses on the display of antibody variable region or antigen-binding fragments. In this study, we constructed a new phage display system that can display full-length IgG antibodies on M13 phage. The phage display vector contains open reading frames (ORFs) encoding full-length the heavy and light chains of the antibody. NcoI/XhoI restriction enzyme sites were used to clone the variable region of the heavy chain into the heavy chain ORF, and SalI/NotI sites were used to clone the light chain variable region. SnaBI and SbfI restriction enzyme sites were designed between the cloning sites of heavy and light chains, respectively, to increase the cloning efficiency. The full-length antibodies of nivolumab against programmed death factor 1, trastuzumab against human epidermal growth factor 2, diL2K against the cluster of differentiation 3 epsilon, and adalimumab against tumor necrosis factor- alpha were displayed on phage with the vector. Phage-displayed antibodies showed their original antigen-binding activity. An amber codon shifted the vector to express IgG in non-suppressed Escherichia coli. The heavy and light chains of the E. coli-expressed antibodies could be detected through western blotting, and the antigen-binding activity was confirmed using an enzyme-linked immunosorbent assay. Biopanning was carried out with a model phage display antibody library, and the results showed that the novel phage system could be used for antibody library construction and highly efficient antibody screening. The reported system is the first full-length antibody phage display system.

抗体噬菌体展示技术在单克隆抗体的开发、抗体的人源化、亲和力进化等方面发挥着重要作用。迄今为止，抗体噬菌体展示主要集中在抗体可变区或抗原结合片段的展示。在这项研究中，我们构建了一个新的噬菌体展示系统，可以在 M13 噬菌体上展示全长 IgG 抗体。噬菌体展示载体包含编码全长抗体重链和轻链的开放阅读框 (ORF)。Nco I/ Xho I限制酶位点用于将重链可变区克隆到重链ORF中，Sal I/ Not I位点用于克隆轻链可变区。斯纳BI 和Sbf I 限制酶位点分别设计在重链和轻链的克隆位点之间，以提高克隆效率。抗程序性死亡因子 1 的纳武单抗、抗人表皮生长因子 2 的曲妥珠单抗、抗分化簇 3 epsilon 的 diL2K 和抗肿瘤坏死因子-α 的阿达木单抗的全长抗体与载体一起展示在噬菌体上。噬菌体展示的抗体显示出它们最初的抗原结合活性。琥珀密码子转移载体以在非抑制性大肠杆菌中表达 IgG 。大肠杆菌的重链和轻链表达的抗体可以通过蛋白质印迹法检测到，抗原结合活性通过酶联免疫吸附试验得到证实。使用模型噬菌体展示抗体库进行生物淘选，结果表明该新型噬菌体系统可用于抗体库构建和高效抗体筛选。报道的系统是第一个全长抗体噬菌体展示系统。