SBIR RAPID: Plant Bioproduction of Antibodies for the Treatment of Ebola Infection

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Rapid Response Research (RAPID) 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 current Ebola outbreak, a new drug was tested in infected patients that is based on a tobacco-produced Ebola antibody cocktail called ZMapp (Mapp Biopharmaceutical, Inc, San Diego, CA). Unfortunately, the company's supply of antibody was quickly depleted, and 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 trichome glands. The goal is to generate a line of N. tabacum plants that is optimized for antibody production in plant trichomes to provide an urgently needed biomanufacturing platform for the large-scale production of antibodies that may be used in the treatment of Ebola infection. This SBIR RAPID 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. 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. Other expression hosts (Chinese hamster ovary cells, yeast) yield product with reduced potency, and are not considered 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 demonstrate secretion of Ebola antibodies, and to generate a line of N. tobacum for optimized antibody glycosylation.