Monoclonal antibodies (mAbs) are widely utilized as therapeutic drugs for various diseases, such as cancer, autoimmune diseases, and infectious diseases. Using the avian-derived B cell line DT40, we previously developed an antibody display technology, namely, the ADLib system, which rapidly generates antigen-specific mAbs. Here, we report the development of a human version of the ADLib system and showcase the streamlined generation and optimization of functional human mAbs. Tailored libraries were first constructed by replacing endogenous immunoglobulin genes with designed human counterparts. From these libraries, clones producing full-length human IgGs against distinct antigens can be isolated, as exemplified by the selection of antagonistic mAbs. Taking advantage of avian biology, effective affinity maturation was achieved in a straightforward manner by seamless diversification of the parental clones into secondary libraries followed by single-cell sorting, quickly affording mAbs with improved affinities and functionalities. Collectively, we demonstrate that the human ADLib system could serve as an integrative platform with unique diversity for rapid de novo generation and optimization of therapeutic or diagnostic antibody leads. Furthermore, our results suggest that libraries can be constructed by introducing exogenous genes into DT40 cells, indicating that the ADLib system has the potential to be applied for the rapid and effective directed evolution and optimization of proteins in various fields beyond biomedicine.

单克隆抗体 (mAb) 被广泛用作各种疾病的治疗药物，例如癌症、自身免疫性疾病和传染病。使用禽类B细胞系DT40，我们之前开发了一种抗体展示技术，即ADLib系统，可快速产生抗原特异性mAb。在这里，我们报告了人类版本的 ADLib 系统的开发，并展示了功能性人类 mAb 的简化生成和优化。首先通过用设计的人类对应物替换内源性免疫球蛋白基因来构建定制文库。从这些文库中，可以分离产生针对不同抗原的全长人 IgG 的克隆，例如拮抗性 mAb 的选择。利用鸟类生物学，通过将亲本克隆无缝多样化到二级文库中，然后进行单细胞分选，以直接的方式实现了有效的亲和力成熟，从而快速提供具有改进亲和力和功能的 mAb。总的来说，我们证明人类 ADLib 系统可以作为一个具有独特多样性的综合平台，用于快速从头生成和优化治疗或诊断抗体先导。此外，我们的研究结果表明，可以通过将外源基因引入DT40细胞来构建文库，表明ADLib系统具有应用于生物医学以外各个领域快速有效的定向进化和优化蛋白质的潜力。