Tobacco Plants Make Vaccinations for HIV Possible
Plants can produce antibodies that can provide protection against HIV infection. RWTH Professor Rainer Fischer, Chair of Molecular Biotechnology at RWTH Aachen and Director of the Fraunhofer Institute for Molecular Biology and Applied Ecology explains: “Substances such as the neutralizing antibody 2G12 offer protection against infection from pathogens. It binds a particular viral protein, the gp120 protein, to the surface of the virus, so that the pathogen can no longer dock on the immunocompetent cells. The antibodies have been produced in animal cell cultures till now. The process is elaborate and expensive. So-called molecular farming presents a safer and, above all, cheaper alternative.” Molecular farming is a process in biotechnology, in which active pharmaceutical ingredients are produced with the help of agriculture.
Nestled in the EU project "PharmaPlanta," Fischer and his team have been working since 2004 on important foundations for the production of the antibody in genetically altered plants and plant cells. 39 partners from science and industry in 12 different countries are involved in the research project, funded by the European Union. The work was successfully ended through the completion of a clinical trial in London.
In the next five years, Fischer can intensify his work through an Advanced Grant provided by the European Research Council (ERC). The ERC Advanced Grant is targeted towards extraordinarily experienced and excellent researchers. Fischer received the funding above all for the PharmaPlanta project, which he led together with Professor Julian Mavon of St. George’s Hospital Medical School in London. During this time, he managed to prepare material for a clinical trial of the antibody.
The anitbody had to first be identified. Then, it had to be crossed five times, in order to obtain the corresponding stable seeds. In order for the antibody to be harvested from the plant, researchers plant the gene for the agent in the genotype of the tobacco plant. Tobacco plants are particularly suitable, because they are relatively easy to change genetically. Additionally, the plants are neither food nor part of the food chain. Furthermore, they grown in tropical regions and are widespread in developing countries. They can be grown "in the region for the region" and processed. "The planted protein is automatically produced when the plant grows," says Fischer. During production, the leaves are washed, minced, and then extracted through a series of four to five filtration and chromatography steps. "The clear extract was successfully tested in preclinical safety studies at the end of 2008, without negative effects appearing," reported Fischer.
A total of 800 kilograms of plant material from the institute’s own greenhouse was produced in order to obtain new ingredients in accordance with the guidelines of the European Medical Agency (EMA) and to prepare them for a clinical trial. Within the framework of the ERC Advanced Grant, molecular farming will be expanded as a prophylaxis against other illnesses, such as rabies. The cultivation and isolation process will also be simplified and optimized. "We are now concentrating on the needs of the developing countries. Patients cannot be sufficiently treated due to the high cost of medicine," says Fischer. He emphasizes, "We see hope for millions of people with molecular farming."