Infection Site Targeted Antitoxin Antibody (ISTAb) against Bacillus anthracis

针对炭疽杆菌的感染部位靶向抗毒素抗体 (ISTAb)

• 批准号: 10817474
• 负责人: Rajan P Adhikari
• 金额: $ 31.5万
• 依托单位: ABVACC, INC.
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10817474
• 关键词: Infection; Site; Targeted; Antitoxin; Antibody

Project Summary Bacillus anthracis (Ba) is a Gram-positive spore forming bacterium that is listed as an agent of highest concern (Category A) by NIAID and CDC. Ba is easy to grow, and its spores can be formulated into highly stable powder form and disseminated as aerosol or used to contaminate food or water. In 2001, letters laced with powdered anthrax spores were mailed to several US politicians. Twenty-two people, including 12 mail handlers, were infected, and five of them died. B. anthracis virulence largely depends on two key toxins generated by combination of the protective antigen (PA) associated with either lethal factor (LF) or edema factor (EF). Although some oral antibiotics and a vaccine are available for use, in practice these treatments cannot adequately address the adverse effects of bacterial toxins released post exposure. In our recently completed R41 project, we developed and tested a novel approach to target neutralizing anti-PA antibodies specifically to the site of infection in vitro and in vivo. The approach exploits the cell wall targeting domains (CWT) of well characterized phage endolysins (PlyG, PlyL and PlyB) that bind with species-specificity and high affinity to cell wall components of Ba. These CWTs are fused to specific antitoxin neutralizing monoclonal antibodies (mAbs) to generate Infection Site Targeted Antitoxin antibodies (ISTAbs). ISTAb technology provides two therapeutic advantages: immediate toxin neutralization at the site of infection preventing toxemia, and opsonophagocytic killing by phagocytes to simultaneously clear both bacteria and toxin. We compared nine ISTAb candidates (three CWTs and three mAbs) based on in vitro assays (cell binding and toxin neutralization) and selected one ISTAb (AVP-21D9-PlyG) for pre- and post-challenge in vivo studies in mice. This ISTAb exhibited significantly higher level of protection than the parental IgG. This R42 is aimed to take this lead ISTAb molecule into the next level in therapeutic pipeline. In this proposal, we will produce and extensively characterize next-generation AVP-21D9-PlyG ISTAbs, including stability and in vivo efficacy studies in mice and nonhuman primates (NHP), and develop a stable formulation. In Aim 1, we will use computer-aided optimizations to generate 3-5 ISTAb variants to remove potential liabilities that may complicate downstream development. In Aim 2, two lead candidates will be tested in mouse models. One lead molecule will be tested in an NHP model for PK and post-challenge efficacy. In Aim 3: The final ISTAb will be subjected to accelerated stability and PK studies, formulation, and generation of stable cell lines in CHO-S cells. The combination of immediate toxin clearance, phagocytic killing, and concurrent use of antibiotics, is expected to create synergy and yield a treatment that is far superior to the current standard of care. Furthermore, this technology can be applied to a variety of other bacterial pathogens where toxins play a key role in pathogenesis. Overall, this approach has board application as a platform technology across multiple pathogens.

项目摘要 炭疽芽孢杆菌（BA）是一种革兰氏阳性孢子，形成细菌，被列为最高的药物 NIAID和CDC的关注（A类）。 Ba很容易生长，并且可以将其孢子配合到高度 稳定的粉末形式并以气溶胶的形式散布或用来污染食物或水。在2001年，字母系好 炭疽孢子粉被邮寄给几位美国政客。 22个人，包括12封邮件 处理人员被感染，其中五人死亡。 B.炭疽病的毒力在很大程度上取决于两个关键的毒素 通过与致命因子（LF）或水肿相关的保护性抗原（PA）的组合产生 因子（EF）。尽管有一些口服抗生素和疫苗可供使用，但实际上这些治疗方法 无法充分解决暴露后释放的细菌毒素的不利影响。在我们最近 完成的R41项目，我们开发并测试了一种新的方法来靶向中和抗PA抗体 专门针对体外和体内感染部位。该方法利用细胞壁靶向域 （CWT）的噬菌体内olysin（plyg，plyl和plyb）的（CWT）与物种特异性和 对BA的细胞壁成分的高亲和力。这些CWT融合到特定的抗毒素中和 单克隆抗体（mAb）产生靶向抗毒素抗体（ISTABS）的感染部位。 iStab 技术提供了两个治疗优势：在感染部位立即中和 防止毒血症和吞噬细胞杀死吞噬细胞同时清除细菌和 毒素。我们根据体外测定法（细胞 结合和毒素中和）并选择一个ISTAB（AVP-21D9-PLYG），用于挑战前后 小鼠的体内研究。与父母IgG相比，ISTAB表现出明显更高的保护水平。这 R42的目的是将该铅ISTAB分子纳入治疗管道的新水平。在此提案中， 我们将产生并广泛地表征下一代AVP-21D9-PLYG ISTAB，包括稳定性 以及在小鼠和非人类灵长类动物（NHP）中的体内功效研究，并开发出稳定的配方。在 AIM 1，我们将使用计算机辅助优化来生成3-5个ISTAB变体以消除潜在 可能使下游发展复杂的负债。在AIM 2中，将在AIM 2中进行测试 鼠标模型。一个铅分子将在NHP模型中测试，以获得PK和挑战后的积极性。在 目标3：最终的iSTAB将受到加速稳定性和PK研究，配方和产生 Cho-S细胞中稳定细胞系的稳定细胞系。立即毒素清除，吞噬细胞杀戮和 同时使用抗生素，预计将产生协同作用，并产生一种远比该治疗 当前的护理标准。此外，该技术可以应用于其他各种细菌 病原体中毒素在发病机理中起关键作用。总体而言，这种方法具有董事会申请 跨多种病原体的平台技术。