School of Pharmacy, The Center for Antibody Medicine of Ministry of Education, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
PLoS One. 2012;7(8):e43845. doi: 10.1371/journal.pone.0043845. Epub 2012 Aug 29.
Botulinum neurotoxins (BoNTs), the causative agents for life-threatening human disease botulism, have been recognized as biological warfare agents. Monoclonal antibody (mAb) therapeutics hold considerable promise as BoNT therapeutics, but the potencies of mAbs against BoNTs are usually less than that of polyclonal antibodies (or oligoclonal antibodies). The confirmation of key epitopes with development of effective mAb is urgently needed.
We selected 3 neutralizing mAbs which recognize different non-overlapping epitopes of BoNT/B from a panel of neutralizing antibodies against BoNT/B. By comparing the neutralizing effects among different combination groups, we found that 8E10, response to ganglioside receptor binding site, could synergy with 5G10 and 2F4, recognizing non-overlapping epitopes within Syt II binding sites. However, the combination of 5G10 with 2F4 blocking protein receptor binding sites did not achieve synergistical effects. Moreover, we found that the binding epitope of 8E10 was conserved among BoNT A, B, E, and F, which might cross-protect the challenge of different serotypes of BoNTs in vivo.
The combination of two mAbs recognizing different receptors' binding domain in BoNTs has a synergistic effect. 8E10 is a potential universal partner for the synergistical combination with other mAb against protein receptor binding domain in BoNTs of other serotypes.
肉毒神经毒素（BoNTs）是导致危及生命的人类疾病肉毒中毒的病原体，已被确认为生物战剂。单克隆抗体（mAb）疗法作为 BoNT 疗法具有很大的潜力，但 mAb 对 BoNTs 的效力通常低于多克隆抗体（或寡克隆抗体）。因此，迫切需要确认关键表位并开发有效的 mAb。
我们从针对 BoNT/B 的一组中和抗体中选择了 3 种识别 BoNT/B 不同非重叠表位的中和 mAb。通过比较不同组合组的中和效果，我们发现识别 Syt II 结合位点内非重叠表位的 8E10（针对神经节苷脂受体结合位点）可以与 5G10 和 2F4 协同作用。然而，与 2F4 结合蛋白受体结合位点结合的 5G10 组合并未产生协同作用。此外，我们发现 8E10 的结合表位在 BoNT A、B、E 和 F 中是保守的，这可能在体内对不同血清型的 BoNTs 起到交叉保护作用。
识别 BoNTs 中不同受体结合域的两种 mAb 的组合具有协同作用。8E10 可能是与其他针对不同血清型 BoNTs 蛋白受体结合域的 mAb 进行协同组合的潜在通用伙伴。
