Human monoclonal panel mimicking anthrax immune globulin

即使及时使用抗生素，与吸入性炭疽病相关的死亡率也很高。人们再次担心炭疽芽孢杆菌的孢子可能被用作生物威胁因子，这促使人们寻找一种辅助疗法，可能会降低已知接触者的死亡率。几条证据表明，通过接种疫苗或被动注射的毒素特异性抗体，在吸入性炭疽暴露后治疗中与抗生素具有协同作用。我们已经成功地克隆并表达了组成炭疽杆菌保护性抗原(PA)的人抗体库中的大多数抗体，这些抗体来自AVA疫苗接种的捐赠者的B细胞。从这个完全人类的、PA特异的单抗结合域的集合中，我们建议建立一组中和抗体，作为一种基于工程“多克隆”抗体的治疗方法，以中和8种炭疽毒素。具体地说，我们将1)将所有先前分离的PA特异性抗体克隆转换为适合在真核系统中表达的形式，2)在体外细胞保护实验中鉴定那些中和毒素的副表位，3)鉴定非竞争PA中和克隆的子集，4)在我们的双顺反子ParC/IRES表达载体和所建立的基于Lonza谷氨酰胺合成酶的抗体表达系统中优化抗体表达。我们预计，在拟议的支持期结束时，产品将准备好在动物模型系统中进行体内测试。我们构建的PA特异性面板将是分子定义和表征的，结合了毒素特异性多克隆人血清的优势，并且缺乏与血液衍生产品相关的固有风险。

The mortality rate associated with inhalation anthrax is high, even if antibiotics are administered in a timely manner. Renewed fears that Bacillus anthracis spores may be employed as a biological threat agent have prompted a search for an adjunct therapy that might lower mortality rates in persons known to be exposed. Several lines of evidence suggest that toxin-specific antibodies, acquired either through vaccination or administered passively, work synergistically with antibiotics in post-exposure therapy for inhalation anthrax. We have successfully cloned and expressed the majority of antibodies that comprise the human antibody repertoire specific for the protective antigen (PA) of B. anthracis using B cells from AVA-vaccinated donors. From this collection of fully human, PA-specific monoclonal binding domains, we propose to establish a panel of neutralizing antibodies to be used as an engineered "polyclonal" antibody-based therapeutic to neutralize 8. anthracis toxins. Specifically, we will 1) convert all previously isolated PA-specific antibody clones to a format suitable for expression in eukaryotic systems, 2) identify those paratopes that neutralize toxin in an in vitro cell protection assay, 3) identify a subset of non-competing PA-neutralizing clones, 4) optimize antibody expression both in our bi-cistronic pARC/IRES expression vectors and the established Lonza glutamine synthetase-based antibody expression system. We anticipate a product ready for in vivo testing in an animal model system at the conclusion of the proposed period of support. The PA-specific panel we construct will be molecularly defined and characterized, incorporate the advantages of toxin-specific, polyclonal human sera, and lack the inherent risk associated with blood derived products.