Byrne M P, Smith L A
Department of Immunology and Molecular Biology, Division of Toxinology, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702-5011, USA.
Biochimie. 2000 Sep-Oct;82(9-10):955-66. doi: 10.1016/s0300-9084(00)01173-1.
Botulism is a potentially lethal disease caused by one of seven homologous neurotoxic proteins usually produced by the bacterium, Clostridium botulinum. This neuromuscular disorder occurs through an exquisite series of molecular events, ultimately ending with the arrest of acetylcholine release and hence, flaccid paralysis. The development of vaccines that protect against botulism dates back to the 1940s. Currently, a pentavalent vaccine that protects against BoNT serotypes A-E and a separate monovalent vaccine that protects against BoNT serotype F are available as Investigational New Drugs. However, due to the numerous shortcomings associated with the toxoid vaccines, several groups have efforts towards developing next-generation vaccines. Identifying a synthetic peptide that harbors a neutralizing epitope is one approach to a BoNT vaccine, while another employs the use of a Venezuelan equine encephalitis virus replicon vector to produce protective antigens in vivo against BoNT. The strategy used in our laboratory is to design synthetic genes encoding non-toxic, carboxy-terminal fragments of the C. botulinum neurotoxins (rBoNT(H(C))). The gene products are expressed in the yeast, Pichia pastoris, and purified to greater than 98% with yields typically ranging from 200-500 mg per kg of wet cells. Protective immunity to the purified products against high-level challenges of neurotoxin is elicited in mice and in non-human primates. A pre-Investigational New Drug meeting was held with the Food and Drug Administration, and the next milestone for the vaccine candidates will be clinical trials.
肉毒中毒是一种潜在的致命疾病，由通常由肉毒杆菌产生的七种同源神经毒性蛋白之一引起。这种神经肌肉疾病通过一系列精妙的分子事件发生，最终以乙酰胆碱释放的停止告终，进而导致弛缓性麻痹。预防肉毒中毒的疫苗研发可追溯到20世纪40年代。目前，一种预防A-E型肉毒毒素的五价疫苗和一种单独的预防F型肉毒毒素的单价疫苗作为研究性新药可供使用。然而，由于类毒素疫苗存在诸多缺点，几个研究小组一直在努力研发下一代疫苗。鉴定具有中和表位的合成肽是肉毒毒素疫苗的一种方法，另一种方法是利用委内瑞拉马脑炎病毒复制子载体在体内产生针对肉毒毒素的保护性抗原。我们实验室采用的策略是设计编码肉毒杆菌神经毒素无毒羧基末端片段的合成基因（rBoNT(H(C))）。基因产物在毕赤酵母中表达，并纯化至纯度大于98%，产量通常为每千克湿细胞200-500毫克。纯化产物在小鼠和非人类灵长类动物中引发了针对神经毒素高水平攻击的保护性免疫。与美国食品药品监督管理局召开了研究性新药前会议，候选疫苗的下一个里程碑将是临床试验。
