Ebola Drug From Tobacco Part of Promising Therapies.

http://www.bloomberg.com/news/2014-08-06/ebola-drug-from-tobacco-part-of-promising-therapies.html

On a small plot of land incongruously tucked amid a Kentucky industrial park sit five weather-beaten greenhouses. At the site, genetically-modified tobacco plants contain one of the most promising hopes for developing an effective treatment for the deadly Ebola virus.

The plants contain designer antibodies developed by San Diego-based Mapp Biopharmaceutical Inc. and are grown in Kentucky by a unit ofReynolds American Inc. (RAI) Two stricken U.S. health workers received an experimental treatment containing the antibodies in Liberia last week. Since receiving doses of the drug, both patients’ conditions have improved.

Tobacco plant-derived medicines, which are also being developed by a company whose investors include Philip Morris International Inc. (PM), are part of a handful of cutting edge plant-based treatments that are in the works for everything from pandemic flu to rabies using plants such as lettuce, carrots and even duckweed. While the technique has existed for years, the treatments have only recently begun to reach the marketplace.

“Producing antibodies in plants is faster and less expensive than traditional manufacturing,” said Mary Kate Hart, an immunology researcher who did pioneering research on Ebola antibodies for the U.S. Army. She now is chief scientific officer for DynPort Vaccine Co.

The path to creating antibodies in tobacco plants starts with mice, which are injected with a vaccine carrying Ebola virus proteins, Erica Ollman Saphire, a molecular biologist at the Scripps Research Institute, said in a telephone interview.

“They come up with a hundred antibodies, and the question is, which ones do you use?” she said.

Designer Antibodies

Researchers try to identify the best antibodies in the lab, before testing them on mice, then eventually on monkeys. Mapp’s experimental drug, dubbed ZMapp, has three antibodies, which work together to alert the immune system and neutralize the Ebola virus, she said.

This is where the tobacco comes in: the plants are used as hosts to grow large amounts of the antibodies. Genes for the desired antibodies are fused to genes for a natural tobacco virus, Charles Arntzen, a plant biotechnology expert at Arizona State University, said in an Aug. 4 telephone interview.

The tobacco plants are then infected with this new artificial virus, and antibodies are grown inside the plant. Eventually, the tobacco is ground up and the antibody is extracted, Arntzen said.