SBIR Phase II: Plant Bioproduction of Therapeutics and Antibodies for the Treatment of Ebola and Other Diseases

这项小企业创新研究（SBIR）第二阶段项目的更广泛影响/商业潜力将是开发基因工程烟草植物，这些烟草植物可产生用于治疗埃博拉病毒感染者的抗体。在最近的埃博拉疫情中，一种基于抗体的新药物被证明对治疗感染患者有效，这种药物是基于一种名为ZMapp的瞬时烟草产生的埃博拉抗体鸡尾酒（Mapp biopharmactical, Inc ., San Diego， CA）。不幸的是，由于生产方法无法满足需求，马普生物制药的抗体供应很快就耗尽了。该提案中的技术创新是在烟叶表面结构的腺体细胞内靶向生产抗体，称为腺分泌毛状体。研究目标将是证明烟草毛状腺分泌埃博拉病毒抗体。我们的目标是培育一种适合在植物毛状体中生产抗体的烟草N. tabacum植物系，为大规模生产抗体提供生物制造平台，这些抗体可能用于治疗埃博拉感染，以及未来的其他疾病。该SBIR第二期项目建议使用最近开发的基于植物的生物制造系统来扩大用于治疗性治疗的埃博拉病毒抗体的生产。马普生物制药公司生产了一种基于烟草植物瞬态基因表达系统中产生的埃博拉病毒抗体的药物。使用该系统，他们已经鉴定出一种糖基化抗体变体（糖型），具有增强的抗体依赖性细胞毒性。该公司利用N. benthiamiana的糖基转移酶敲除系和瞬时表达策略，利用植物生产糖基化抗体，使天然免疫效应细胞获得最佳招募（Olinger et al., 2012）。其他表达宿主（中国仓鼠卵巢细胞、酵母）的产率较低，不适合替代。为了利用现有的植物表达技术回收活性抗体，Mapp必须对植物进行破坏性收获，并从植物组织匀浆中分离抗体。不幸的是，这种方法还不能产生足够的抗体来满足需求。所提出的方法将允许在烟草植物中大规模生产抗体。此外，该系统将使用不需要破坏性均质化的抗体收集策略，因为抗体将分泌到叶子表面，并通过洗涤回收。该项目的目标是通过系统优化，提高植物生产抗体的功能，扩大生产规模，并进一步降低生产成本。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project will be the development of genetically engineered tobacco plants that produce antibodies for the treatment of individuals infected with the Ebola virus. In the recent Ebola outbreak, a new antibody-based drug was shown to be effective in treating infected patients that was based on a transient tobacco-produced Ebola antibody cocktail called ZMapp (Mapp Biopharmaceutical, Inc, San Diego, CA). Unfortunately, Mapp Biopharmaceutical's supply of antibody was quickly depleted, as the manufacturing method was not able to keep up with demand. The technological innovation in this proposal is the targeted production of antibodies within the gland cells of the tobacco leaf surface structures called glandular secreting trichomes. The research objectives will be to demonstrate the secretion of antibodies to the Ebola virus from tobacco trichome glands. The goal is to generate a line of N. tabacum plants that is optimized for antibody production in plant trichomes to provide a biomanufacturing platform for the large-scale production of antibodies that may be used in the treatment of Ebola infection, and in the future, other diseases.This SBIR Phase II project proposes to use a recently developed plant-based biomanufacturing system to scale-up the production of antibodies to the Ebola virus for use as a therapeutic treatment. Mapp Biopharmaceutical has produced a drug based on antibodies to the Ebola virus produced in a tobacco plant transient gene expression system. Using this system, they have identified a glycosylated antibody variant (glycoform) with enhanced antibody-dependent cell cytotoxicity. Using glycosyl-transferase knockout lines of N. benthiamiana and transient expression strategies, the company utilizes plants to produce glycosylated antibodies that produce optimal recruitment of natural immune effector cells (Olinger et al., 2012). Other expression hosts (Chinese hamster ovary cells, yeast) yield product with reduced potency, and are not suitable alternatives. To recover active antibody with their current plant expression technology, Mapp Biopharmaceutical must destructively harvest plants, and isolate antibody from plant tissue homogenates. Unfortunately, this method has not been able to produce enough antibodies to satisfy the demand. The proposed method will allow for the production of antibodies in tobacco plants in large scale. In addition, the proposed system will use antibody harvesting strategies that do not require destructive homogenization as the antibodies will be secreted onto the surface of the leaf, and recovered by washing. The goals of this project are to increase the functionality of plant-produced antibodies, scale-up production, and reduce the costs of production further through system optimization.