Vaccines Against Botulism

肉毒杆菌神经毒素（BoNT）是一个庞大的蛋白毒素家族，分为七个血清型（A-G） 这是基于抗BoNT血清对每种BoNT血清型的有限交叉保护。BoNT是毒性最强的蛋白质 人类已知的肉毒杆菌和肉毒杆菌中毒的病原体。目前，还没有获得许可的疫苗， 肉毒杆菌中毒和实验性五血清型类毒素疫苗以前可从疾病预防控制中心的风险 人口在2011年停止。因此，需要开发一种有效的BoNT疫苗。 针对所有BoNT血清型，以保护处于危险中的人免受暴露，包括处于危险中的平民，首先 救援人员、军方和研究人员。BoNT被组织成三个参与催化（LC）的结构域， LC易位（HCN）和受体结合（HCC）。早期的努力集中在开发重组 基于HCC的疫苗克服了化学灭活类毒素的缺点，但最近的研究表明， 显示重组全长BoNT疫苗比包含受体的疫苗更有效 结合域此外，ELISA研究暗示HCN易位结构域作为免疫显性蛋白， 在重组全长BoNT疫苗接种的小鼠中， 天然肉毒杆菌毒素挑战。这支持了重组全长无毒BoNT 突变以抑制毒素作用的三个独立功能（催化、LC易位和受体）， 结合）将提高远系繁殖群体的疫苗效力。 目前的研究将利用信息学和评估的结构功能比对的七个 肉毒杆菌毒素的血清型，沿着细胞生物学分析和抗体的免疫学评估 (IgM和IgG）应答的动物进行免疫接种的重组全长BoNT疫苗与化学免疫接种的动物相比， 灭活的肉毒杆菌类毒素。将测试两种肉毒杆菌毒素疫苗模型：单次高剂量BoNT 用于快速应对BoNT暴露威胁的疫苗和用于长期保护的低剂量BoNT疫苗 对抗肉毒杆菌毒素将对低剂量保护性疫苗与化学灭活疫苗进行对比试验 肉毒杆菌类毒素在小鼠和兔子中的作用。对细菌毒素结构-功能特性的理解 允许生产更安全、更便宜、更容易生产的下一代疫苗， 与化学灭活的类毒素相比，具有遗传可塑性，可进行快速修饰。本报告中提出的研究 应用为毒素疫苗学的这些进展提供了未来的方向。

The botulinum neurotoxins (BoNT) are a large protein toxin family grouped into seven BoNT serotypes (A-G) based upon limited cross protection of -sera against each BoNT serotype. BoNT are the most toxic proteins known for humans and the causative agent of botulism. Currently, there is no licensed vaccine against botulism and the experimental penta-serotype toxoid vaccine previously available from the CDC for at-risk populations was discontinued in 2011. Thus, there is a need to develop a potent and effective BoNT vaccine against all BoNT serotypes to protect at-risk humans from exposure, including civilians in harm’s way, first responders, the military, and researchers. BoNT are organized into three domains involved in catalysis (LC), LC translocation (HCN), and receptor binding (HCC). Earlier efforts have focused on developing recombinant HCC-based vaccines to overcome the shortcomings of chemically inactivated toxoids, but recent studies have shown that recombinant full-length BoNT vaccines are more potent than vaccines comprising the receptor binding domain. In addition, ELISA studies implicated the HCN translocation domain as the immunodominant domain, not the HCC receptor binding domain, in recombinant full-length BoNT vaccinated mice surviving native botulinum toxin challenge. This supports the hypothesis that a recombinant full-length non-toxic BoNT mutated to inactivate the three independent functions of toxin action (catalysis, LC translocation, and receptor binding) will improve vaccine potency for outbred populations. The current study will utilize informatics and assessment of structure-function alignments of the seven serotypes of botulinum toxin, along with cell biological analysis and immunological assessment of the antibody (IgM and IgG) response of animals immunized with recombinant, full-length BoNT vaccine versus chemically inactivated botulinum toxoid. Two models for botulinum toxin vaccines will be tested: a single high dose BoNT vaccine for rapid response to threats of BoNT exposure and a low dose BoNT vaccine for long term protection against BoNT exposure. The low dose protective vaccine will be tested versus chemically inactivated botulinum toxoid in mice and rabbits. Understanding of the structure-function properties of bacterial toxins allows production of Next Generation vaccines that are safer, less expensive, easier to produce, and genetically malleable for rapid modification than chemically inactivated toxoids. The studies proposed in this application provide future directions for these advances in toxin vaccinology.