Development of a Therapeutic for Staphylococcal Enterotoxin B

40多年来，美国军方一直认识到毒素SEB(葡萄球菌肠毒素B)构成了严重的致残和致命威胁。在过去的15年里，各种生化和分子研究表明，SEB作为一种超抗原，刺激大量的T细胞反应，导致一种称为中毒性休克综合征的全身性疾病。呼吸道和其他特定组织的炎症反应也使SEB暴露于作为生物武器的严重威胁中。根据我们目前对SEB的结构、生化和作用机制的了解，我们的假设是，我们可以通过设计高亲和力中和剂来开发针对SEB暴露的特异和有效的治疗方法。目标是进一步开发一种名为G5-8的抗SEB的先导治疗剂。G5-8是一种可溶性T细胞受体，是一个14 kDa的可变区，以前已经被设计成以皮摩尔亲和力与SEB结合。在动物模型中的结果表明，G5-8对全身性SEB介导的疾病和肺暴露于SEB具有疗效。本项目的目标是确定是否可以通过与免疫球蛋白(Ig)Fc区的融合来改善V5-8的药代动力学特性，并在当前良好的制造规范条件下开始扩大VíáG5-8或其Ig融合衍生物的生产。 该项目将涉及四个机构的协调伙伴关系：伊利诺伊大学厄巴纳-香槟分校(UIUC)、明尼苏达大学(UMN)、生物技术公司ImmuVen和合同生物制品制造公司Cangene。ImmuVen成立的目的是通过汇集商业、知识产权、科学和产品开发专业知识来开发这种用于临床的产品。加拿大公司Cangene是参与美国政府在生物制品领域的合同工作的最大和最有经验的公司之一。他们的专业知识对于cGMP的生产至关重要，其水平足以用于额外的临床前研究，并最终达到第一阶段临床研究的水平。伊利诺伊大学和明尼苏达大学在蛋白质特性、受体生物化学、T细胞分析和SEB引起的疾病的动物模型方面提供专业知识。该项目的具体目标是：(1)表达和纯化具有皮摩尔亲和力的与SEB结合的可溶性Väü5.2结构域和免疫球蛋白融合；(2)体外测试与具有皮摩尔亲和力的SEB结合的可溶Väuv结构域和免疫球蛋白融合；(3)在SEB毒性的动物模型中确定药代动力学，并比较可溶Väuv结构域和免疫球蛋白融合的疗效。描述了G5-8或其衍生物产品开发道路上的各种里程碑，最终目标是为暴露于SEB的个人提供治疗。

For over 40 years, the U.S. military has recognized that the toxin SEB (staphylococcal enterotoxin B) poses a serious incapacitating and lethal threat. In the past 15 years, various biochemical and molecular studies have shown that SEB acts as a superantigen, stimulating a massive T cell response that leads to a systemic disease called toxic shock syndrome. Respiratory and other tissue specific inflammatory reactions have also made exposure to SEB a serious threat as a bioweapon. With the knowledge we now have of the structure, biochemistry, and mechanism of action of SEB, it is our hypothesis that we can develop specific and effective treatments for SEB exposure by engineering high-affinity neutralizing agents. The goal is to further develop a lead therapeutic agent called G5-8 against SEB. G5-8 is a soluble T cell receptor, a 14 kDa variable � domain (V�) that has been previously engineered to bind to SEB with picomolar affinity. Results in animal models have shown that G5-8 has efficacy in both systemic SEB-mediated disease and pulmonary exposure to SEB. The goals of the present project are to determine if the pharmacokinetic properties of the V� G5-8 can be improved by fusion to immunoglobulin (Ig) Fc regions, and to begin the scale-up production of V� G5-8, or its Ig fusion derivatives, under current Good Manufacturing Practice conditions. The project will involve a coordinated partnership of four institutions: University of Illinois, Urbana- Champaign (UIUC), University of Minnesota (UMN), ImmuVen, a biotechnology company, and Cangene, a contract biologics manufacturing company. ImmuVen was founded in order to develop this product for clinical use by bringing together business, intellectual property, scientific, and product development expertise. Cangene, a Canadian company, is among the largest and most experienced companies involved in US government contract work in the area of biologics. Their expertise is critical for the cGMP production of V� G5- 8 at levels sufficient for additional pre-clinical studies, and ultimately, Phase I clinical studies. The University of Illinois and the University of Minnesota provide expertise in protein characterization, receptor biochemistry, T cell assays, and animal models of diseases caused by SEB. The specific aims of the project are: (1) To express and purify soluble V� domains and V�-immunoglobulin fusions that bind to SEB with picomolar affinity; (2) To perform in vitro testing of the soluble V� domains and immunoglobulin fusions that bind to SEB with picomolar affinity; (3) To determine pharmacokinetics and compare the efficacy of soluble V� domains and immunoglobulin fusions in animal models of SEB toxicity. Various milestones along the product development path for G5-8, or its derivatives, are described, with the ultimate goal of providing a therapeutic for individuals who are exposed to SEB.