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

小型企业创新研究(SBIR)第二阶段项目的更广泛影响/商业潜力将是开发转基因烟草植物，产生抗体用于治疗感染埃博拉病毒的个人。在最近的埃博拉疫情中，一种新的基于抗体的药物被证明对治疗受感染的患者有效，该药物基于一种名为ZMapp的烟草产生的瞬时埃博拉抗体鸡尾酒(Mapp生物制药公司，加利福尼亚州圣地亚哥)。不幸的是，Mapp生物制药公司的抗体供应很快就耗尽了，因为制造方法跟不上需求。这项提议的技术创新是在烟叶表面结构的腺体细胞内有针对性地产生抗体，称为腺体分泌毛状体。这项研究的目标将是证明烟草毛状腺分泌埃博拉病毒抗体。目标是培育一种针对植物毛状体中的抗体生产进行优化的烟草新冠植物系，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，并在未来用于其他疾病的治疗。这个SBIR第二阶段项目提议使用最近开发的基于植物的生物制造系统来扩大埃博拉病毒抗体的生产，用于治疗。Mapp生物制药公司生产了一种基于烟草植物瞬时基因表达系统产生的埃博拉病毒抗体的药物。使用这个系统，他们已经鉴定出一种糖基化抗体变异体(糖型)，具有增强的抗体依赖细胞细胞毒性。利用N.benthiamiana的糖基转移酶基因敲除系和瞬时表达策略，该公司利用植物产生糖基化抗体，从而产生自然免疫效应细胞的最佳招募(Olinger等人，2012年)。其他表达宿主(中国仓鼠卵巢细胞、酵母)产生的产物效价较低，不适合作为替代品。为了利用目前的植物表达技术回收活性抗体，Mapp生物制药公司必须破坏性地采集植物，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。建议的方法将允许在烟草植物中大规模生产抗体。此外，拟议的系统将使用不需要破坏性均质的抗体收集策略，因为抗体将分泌到叶子表面，并通过洗涤回收。该项目的目标是增加植物产生的抗体的功能，扩大生产，并通过系统优化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.