High throughput cytotoxicity screening of anti-HER2 immunotoxins conjugated with antibody fragments from phage-displayed synthetic antibody libraries
High throughput cytotoxicity screening of anti-HER2 immunotoxins conjugated with antibody fragments from phage-displayed synthetic antibody libraries
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DOI：
10.1038/srep31878
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发表时间：
2016-08-23
影响因子：
4.6
通讯作者：
Yang, An-Suei
中科院分区：
文献类型：
--
作者：
Hou, Shin-Chen;Chen, Hong-Sen;Yang, An-Suei
免疫毒素是一类重要的基于抗体的治疗剂。免疫毒素的效力取决于作为靶向细胞表面上指定分子的引导模块的抗体片段。噬菌体展示的合成抗体scFv文库提供了丰富的抗体片段候选物作为免疫缀合物的靶向模块，但最佳功能性免疫缀合物的发现受到scFv-有效负载缀合程序的限制。在这项工作中，以高通量形式开发了非共价组装的免疫毒素的细胞毒性筛选，以发现用于递送毒素有效载荷的高功能合成抗体片段。已经从大量的细胞毒性数据中阐明了控制抗体作为靶向模块的效率的原理：（a）基于抗体的靶向模块的表位和互补位是免疫毒素效力的主要决定因素;（B）具有二价基于抗体的靶向模块的免疫毒素通常在细胞毒性效力方面上级具有相应单价靶向模块的免疫毒素;和（c）免疫毒素的效力与细胞表面抗原的密度正相关。这些发现表明，用来自合成抗体文库的大量抗体库针对靶细胞进行筛选，而不受天然抗体应答的限制，可导致免疫缀合物的最佳效力和最小脱靶毒性。
Immunotoxins are an important class of antibody-based therapeutics. The potency of the immunotoxins depends on the antibody fragments as the guiding modules targeting designated molecules on cell surfaces. Phage-displayed synthetic antibody scFv libraries provide abundant antibody fragment candidates as targeting modules for the immunoconjugates, but the discovery of optimally functional immunoconjugates is limited by the scFv-payload conjugation procedure. In this work, cytotoxicity screening of non-covalently assembled immunotoxins was developed in high throughput format to discover highly functional synthetic antibody fragments for delivering toxin payloads. The principles governing the efficiency of the antibodies as targeting modules have been elucidated from large volume of cytotoxicity data: (a) epitope and paratope of the antibody-based targeting module are major determinants for the potency of the immunotoxins; (b) immunotoxins with bivalent antibody-based targeting modules are generally superior in cytotoxic potency to those with corresponding monovalent targeting module; and (c) the potency of the immunotoxins is positively correlated with the densities of the cell surface antigen. These findings suggest that screening against the target cells with a large pool of antibodies from synthetic antibody libraries without the limitations of natural antibody responses can lead to optimal potency and minimal off-target toxicity of the immunoconjugates.