Vaccine Cuisine Could Soon Grace Your Table
Koprowski has worked with a Polish research team that has grown a vaccine against the hepatitis B virus in lettuce. After eating the lettuce, the immune systems of human volunteers started fighting the hepatitis B virus, which causes severe and sometimes fatal liver disease.
Another exciting product is a vaccine that would be used to treat patients with incurable leukemia, a form of blood cancer. Renowned cancer specialist Ronald Levy, MD, chief of the division of oncology at Stanford University in Palo Alto, Calif., developed the vaccine and hopes to begin human tests of the plant product this fall. Because of differences in the tumors between leukemia patients, each vaccine will have to be individualized. Making such a vaccine with conventional techniques takes the better part of a year -- but it takes only six to eight weeks to produce it in a tobacco plant.
"We've been doing clinical trials for about 10 years now, producing [the vaccine] in a variety of ways," Levy tells WebMD. "The plant system has the potential advantage of convenience, simplicity, and perhaps even [strength]."
The strength of the vaccine is a major issue and is one reason why scientists continue to seek plant vaccines that can be eaten, unlike those produced by a tobacco plant, which presumably would have to be inhaled. Oral vaccines stimulate different kinds of immune system responses than their injectable cousins -- and these kinds of immunity can protect the membranes of the nose and mouth where most germs, including RSV, first enter the body.
One of the main goals of Buetow's team is the creation of a vaccine that is affordable for poor nations. "It should be readily adaptable to almost any place that needs it," he says. "That would take care of any problems with shipping -- just grow it locally."
Charles E. Rupprecht, PhD, VMD, chief of the rabies section at the CDC's National Center for Infectious Diseases, agrees that affordability is indeed a major issue driving plant vaccine research. "It's a question of the haves and the have-nots," he says. "Most of the risk is in the developing countries that can't afford current vaccines."