Human Antibodies Produced by Corn Plants
Posted February 1, 1998
Corn on the cob isn't just for summer picnics anymore. Genetic engineers have transplanted a human gene into corn reproductive cells and added other DNA that increases
the cells' production of human antibodies. These antibodies will be used in medical treatment of cancer in human patients. When injected into cancer patients, the antibodies will stick
to cancerous tumor cells, delivering radioisotopes that kill them.
Using human antibodies as drugs is not a new concept, but using plant cells to make human antibodies is. In early attempts at producing antibodies, researchers used
mouse cell cultures. These cloned mouse cells did produce antibodies, but they were not human antibodies. When mouse antibodies were used in humans, there were severe allergic reactions.
Also, mouse cell cultures that produced human antibodies were subject to developing human diseases. Since that time, geneticists have bred cultured cell lines that produce antibodies
that are mostly or completely human. But using cultured cell lines to produce antibodies is a slow process, and the antibodies produced are fairly expensive.
Using corn reproductive cells to make human antibodies is much more efficient and economical than using cultured animal cell lines. Ten thousand liters of animal
cells only produce a kilogram or two of antibodies. One strain of corn can produce about 1.5 kilograms of pharmaceutical-quality antibodies per acre of corn. That means that tens of
thousands of cancer patients could be treated with the antibodies needed to deliver cancer drugs from just 30 acres of corn.
Corn is just one plant that is being investigated for its ability to produce human antibodies. Other plants that have been genetically engineered to produce antibodies
include soybeans and tobacco. Soybeans have been engineered to make antibodies against the herpes simplex virus 2. Tobacco plants have been modified to produce an enzyme that is missing
in people with Gaucher's disease. People with this disease pay as much as $160,000 a year for the protein supplement they need to take. This cost will decrease greatly as soon as tobacco
plants begin producing this human enzyme.
Gibbs, W. Wayt. "Plantibodies." Scientific American, November, 1997, p. 44.