A Novel Recombinant Protein Vaccine Against Ricin Toxin

描述(申请人提供)：蓖麻毒素是一种由蓖麻籽产生的高致命性毒素。它很容易获得，很容易制造，而且有库存。蓖麻毒素在间谍和战争中的使用历史悠久，有记录的中毒事件有750例。美国疾病控制与预防中心将蓖麻毒素列为B类生物制剂。20世纪90年代，美国军方在获得恐怖组织囤积蓖麻毒素的情报后，开始有兴趣开发一种针对蓖麻毒素的疫苗。一种蓖麻毒素类毒素对灵长类动物具有保护作用，但它具有很强的毒性，没有获得FDA的批准。我们已经获得了三个重组的蓖麻毒素A链突变体，它们在小鼠体内既不具有血管泄漏活性，也不具有酶活性。当肌肉注射时，这些突变体可以保护小鼠免受大剂量注射的蓖麻毒素的伤害。我们的目标是将其中一种突变株开发成一种廉价、安全、有效、稳定和“用户友好”的疫苗，可以在大群人中使用。这项建议的具体目的是：1)优化疫苗的生产、纯化、配方和稳定性。2)确定疫苗是否能保护小鼠免受雾化和腹腔注射(I.P.)3)生产一小批良好的实验室操作(GLP)最佳候选疫苗，并使用最佳给药途径为六只成年狒狒(三只雄性和三只雌性)接种疫苗。当这三个目标完成后，疫苗应该准备好进行两个物种的急性毒理学研究，并扩大到人类第一阶段临床试验。

DESCRIPTION (provided by applicant): Ricin is a highly lethal toxin produced by castor beans. It is readily available, easy to make, and stockpile. Ricin has a long history of use in espionage and warfare with a documented 750 cases of intoxication. Ricin is classified by the CDC as a Class B biothreat. In the 1990s, the U.S. Military became interested in developing a vaccine against ricin after obtaining information that this toxin was being stockpiled by terrorist organizations. A ricin toxoid is protective in primates, but it is quite toxic and did not receive FDA approval. We have generated three recombinant mutants of ricin's A chain which are devoid of both vascular leak activity and enzymatic activity in mice. When injected i.m., these mutants protect mice against very large doses of injected ricin. Our goal is to develop one of these mutants into an inexpensive, safe, effective, stable, and "user-friendly" vaccine which can be administered to large groups of people. The specific Aims of this proposal are: 1) to optimize production, purification, formulation and stability of the vaccine. 2) to determine whether the vaccine will protect mice against aerosolized as well as intraperitoneal (i.p.) ricin challenge and if so, the best method of immunization (i.m., oral, or intranasal) to protect animals for the longest period of time and 3) to produce a small good laboratory practice (GLP) batch of the best candidate vaccine and use the best route of administration to immunize six adult baboons (three males and three females). When these three aims are completed, the vaccine should be ready for acute toxicology studies in two species and scale-up for Phase 1 clinical trials in humans.