In pharming, scientists isolate the gene for the protein they want to grow, then attach it to tiny gold beads that they shoot into a developing corn plant with a device called a gene gun. As those newly engineered plants grow, they produce corn that's full of the protein made by their new gene. Pharmers harvest that corn and grind it, and scientists extract the pharmaceutical proteins using giant centrifuges and filtering columns. (For a variety of reasons, corn is the most commonly used pharm crop, but the process works similarly in plants from tomatoes to lettuce to tobacco.) The relative simplicity and easy scalability of such nature-based manufacturing brings a staggering potential for boosting profits: For a few million dollars, a pharm company can produce the same amount of protein each year on a 200-acre field that a pharmaceutical company could make for hundreds of millions in a factory. If a pharmer like Carlson wants to increase production, he doesn't spend millions on machinery -- he simply plants more acres.
Though no pharmed products have made it into stores yet, they aren't far off. A company called ProdiGene -- the company that's been stocking Curt Carlson's fields -- has started marketing a corn-produced enzyme that's used to create insulin, and other drugs have undergone early clinical tests. Furthest along is a tobacco-produced cancer vaccine made by Large Scale Biology of Vacaville, California. It creates personalized vaccines for patients with non-Hodgkin's lymphoma by using tobacco plants to grow proteins from each patient's cancer. Those proteins are injected back into the patient, where they trick the body into seeing the cancer cells as foreign invaders and destroying them. Such personalized medicine has long been a dream of medical researchers, who have created similar vaccines by growing tumor proteins in cell culture. That effort has never fully succeeded because of high costs and low productivity -- it takes more than $10,000 and
12 months to produce a cancer vaccine using cell culture, but Large Scale Biology says it can make one in six weeks for "substantially less" in tobacco plants. Early clinical trial results, presented at the American Society of Hematology in December, show that these treatments are safe and may be effective.
Other pharmed drugs and vaccines are in clinical trials
or soon will be: corn-produced drugs for cystic fibrosis, pancreatic disease and herpes; vaccines for cholera, measles and other diseases. According to Charles Arntzen, an Arizona State University plant biologist who developed the first plant-made vaccines, 40 acres of tomatoes could produce enough hepatitis B vaccine to inoculate all newborns in China. And pharming's potential doesn't stop with drugs and vaccines -- ProdiGene corn also grows a chicken protein for medical diagnostic kits, a biological bleach and an artificial sweetener 2,000 times sweeter than sugar. "The proteins [plants] can make are limitless," says plant molecular biologist Roger Beachy, who runs the Donald Danforth Plant Science Center in St. Louis.
Now if only they could keep those proteins to themselves.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.