Neutralization of Typhoid Toxin by Alpaca-Derived, Single-Domain Antibodies Targeting the PltB and CdtB Subunits.
Neutralization of Typhoid Toxin by Alpaca-Derived, Single-Domain Antibodies Targeting the PltB and CdtB Subunits.
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DOI：
10.1128/iai.00515-21
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发表时间：
2022-02-17
影响因子：
3.1
通讯作者：
Song J
中科院分区：
文献类型：
--
作者：
Dulal HP;Vance DJ;Neupane DP;Chen X;Tremblay JM;Shoemaker CB;Mantis NJ;Song J
伤寒毒素是由引起伤寒的细菌病原体伤寒沙门氏菌分泌的，对免疫细胞和脑内皮细胞有趋向性。在这里，我们从伤寒类毒素免疫的羊驼中生成了骆驼单域抗体 (VHH) 文库，并鉴定了在聚糖受体结合 PltB 和核酸酶 CdtB 上选择的 41 个 VHH。通过竞争酶联免疫吸附测定 (ELISA) 对每个基于序列的家族表现出有效体外中和活性的 VHH 进行表位分箱，产生 6 个不同的 VHH、2 个抗 PltB（T2E7 和 T2G9）和 4 个抗 CdtB VHH（T4C4、T4C12、T4E5 和 T4E8），其体内中和活性与相关研究了毒素中和机制。我们发现，T2E7、T2G9 和 T4E5 在体内有效中和伤寒毒素，给予致死剂量伤寒毒素的小鼠 100% 存活，并且几乎没有伤寒毒素介导的上运动功能缺陷，这证明了这一点。总的来说，这些结果凸显了紧凑型抗体通过靶向聚糖结合和/或核酸酶亚基来中和伤寒毒素的潜力。
Typhoid toxin is secreted by the typhoid fever-causing bacterial pathogen Salmonella enterica serovar Typhi and has tropism for immune cells and brain endothelial cells. Here, we generated a camelid single-domain antibody (VHH) library from typhoid toxoid-immunized alpacas and identified 41 VHHs selected on the glycan receptor-binding PltB and nuclease CdtB. VHHs exhibiting potent in vitro neutralizing activities from each sequence-based family were epitope binned via competition enzyme-linked immunosorbent assays (ELISAs), leading to 6 distinct VHHs, 2 anti-PltBs (T2E7 and T2G9), and 4 anti-CdtB VHHs (T4C4, T4C12, T4E5, and T4E8), whose in vivo neutralizing activities and associated toxin-neutralizing mechanisms were investigated. We found that T2E7, T2G9, and T4E5 effectively neutralized typhoid toxin in vivo, as demonstrated by 100% survival of mice administered a lethal dose of typhoid toxin and with little to no typhoid toxin-mediated upper motor function defect. Cumulatively, these results highlight the potential of the compact antibodies to neutralize typhoid toxin by targeting the glycan-binding and/or nuclease subunits.