Hu Naijing, Peng Fenghao, Jiang Zhiyang, Wang Zhihong, Peng Shangde, Xing Cong, Liu Yingjun, Li Xinying, Luo Longlong, Chen Guojiang, Xiao He, Wang Jing, Yu Jiyun, Liu Chenghua, Qiao Chunxia, Feng Jiannan
Beijing Institute of Pharmacology and Toxicology, Beijing, 100850, China.
Beijing Institute of Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
Heliyon. 2025 Feb 14;11(4):e42616. doi: 10.1016/j.heliyon.2025.e42616. eCollection 2025 Feb 28.
Botulinum neurotoxin (BoNT) is a highly lethal toxin produced by the anaerobic bacterium Clostridium botulinum, which leads to nerve paralysis following poisoning. At present, there is no specific drug officially approved. Antibodies, particularly single-domain antibodies, represent safe and effective candidates for specific drugs against BoNT. In this study, the receptor-binding domain of botulinum toxin (BoNT/AHC) was utilized to immunize Bactrian camels, resulting in the generation of a nanobody phage library. From this library, a high-affinity binding antibody, designated A1, and a neutralizing antibody, named HM, were successfully obtained through SPR-based screening. The affinity constant of HM for botulinum toxin is 1.08E-11 M. Results from computer simulations indicate that HM binds at the same site as SV2C. Furthermore, experimental findings demonstrate that HM exhibits significant blocking activity at both the binding level and the cellular level. In mouse toxicity experiments, HM has been shown to offer protection against a 20 LD dose of BoNT/A. Consequently, HM mitigates botulinum toxin poisoning in mice by obstructing the binding of AHC to SV2C.
肉毒杆菌神经毒素（BoNT）是由厌氧细菌肉毒梭菌产生的一种高致死性毒素，中毒后会导致神经麻痹。目前，尚无官方批准的特效药物。抗体，尤其是单域抗体，是抗BoNT特效药物的安全有效候选物。在本研究中，利用肉毒杆菌毒素的受体结合域（BoNT/AHC）免疫双峰驼，构建了一个纳米抗体噬菌体文库。通过基于表面等离子体共振（SPR）的筛选，从该文库中成功获得了一种高亲和力结合抗体A1和一种中和抗体HM。HM对肉毒杆菌毒素的亲和常数为1.08E-11 M。计算机模拟结果表明，HM与突触囊泡蛋白2C（SV2C）在同一位点结合。此外，实验结果表明，HM在结合水平和细胞水平上均表现出显著的阻断活性。在小鼠毒性实验中，HM已被证明能对20倍半数致死量（LD）的BoNT/A提供保护作用。因此，HM通过阻断AHC与SV2C的结合减轻小鼠肉毒杆菌毒素中毒。
