ABSTRACT Ricin toxin (RT), extracted from castor bean, is a type II ribosome-inactivating protein (RIP). As a biothreat agent, there is no effective antidote for RT to date, but recent advances in antibody research may have meet this need. This study aimed to produce human single-chain antibody variable fragments (HuscFvs) that bind to and interfere with RT activity for further clinical use. The purified RT component was used in phage biopanning to select ricin-bound HuscFv-displayed phage clones from synthetic (Tomlinson I + J) phage display libraries. The selected HuscFv, named JE11, showed an almost 100% protective effect to HeLa cells by mixing with RT at a 1:1000 ratio in vitro. The antibody showed an 83% protection against injection of 2 × LD50 RT dose mice within 72 h. This research has therapeutic potential for the diagnosis and treatment of RT poisoning.

中文翻译：

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人单链抗体对蓖麻毒素的中和和结合活性

摘要 从蓖麻中提取的蓖麻毒素 (RT) 是一种 II 型核糖体失活蛋白 (RIP)。作为一种生物威胁剂，迄今为止还没有有效的 RT 解毒剂，但最近抗体研究的进展可能已经满足了这一需求。本研究旨在生产结合并干扰 RT 活性的人单链抗体可变片段 (HuscFvs)，以供进一步临床使用。纯化的 RT 组分用于噬菌体生物淘选，以从合成 (Tomlinson I + J) 噬菌体展示文库中选择结合蓖麻蛋白的 HuscFv 展示的噬菌体克隆。选定的 HuscFv，名为 JE11，通过在体外以 1:1000 的比例与 RT 混合，对 HeLa 细胞显示出几乎 100% 的保护作用。该抗体在 72 小时内对注射 2 × LD50 RT 剂量的小鼠具有 83% 的保护作用。