As a category A toxic, the botulinum toxin(BoNT) is responsible for human botulism with an estimated lethal dose of 1 ng/kg which greatly increases the potential risk of use as bioweapons. Therefore, the development of anti-BoNT antibodies is urgent. In this paper, the H_C domain of BoNT/A was purified and immunized with Balb/c mice. Monoclonal antibodies were screened against BoNT/A from 55 stable positive hybridoma cell lines, and one with the strongest neutralizing activity, designated as ML06, was subcloned, sequenced, and classified as IgG1(κ) subclass. The mouse protection assays showed that ML06 can neutralize the toxin of BoNT/A effectively both in vitro and in vivo, in a dose-dependent manner. The therapeutic assays showed that only 20% of mice injected with 4 LD₅₀ BoNT/A can survive another injection of ML06 after 4 h. The prophylaxis assays showed the residual ML06 from mice injected with ML06 two weeks ago can protect mice against 4 LD₅₀ BoNT/A challenge completely. Collectively, our results indicated that ML06 served as a good candidate for further development of immune therapeutics for BoNT/A.

肉毒杆菌毒素（BoNT）作为A类毒物，可导致人肉毒杆菌中毒，估计致死剂量为1 ng / kg，这大大增加了用作生物武器的潜在风险。因此，抗BoNT抗体的开发迫在眉睫。在本文中，BoNT / A的H _C结构域被纯化并用Balb / c小鼠免疫。从55个稳定的阳性杂交瘤细胞系中筛选了针对BoNT / A的单克隆抗体，并将具有最强中和活性的一种抗体命名为ML06，进行亚克隆，测序并归类为IgG1（κ）亚类。小鼠保护实验表明，ML06可在体内外有效中和BoNT / A的毒素，剂量依赖性。治疗性分析表明，仅20％小鼠的4 LD注入₅₀的BoNT / A 4小时后可以生存ML06的另一种注射。预防性试验显示，两周前注射ML06的小鼠体内残留的ML06可以完全保护小鼠免受4 LD ₅₀ BoNT / A攻击。总的来说，我们的结果表明，ML06是进一步开发BoNT / A免疫疗法的良好候选者。