Vegetable vaccines

Vegetarian Times, Feb, 1996

This month, scientists begin recruiting volunteers for the first trial of a vegetable genetically engineered to vaccinate humans against common diseases when eaten. If successful, the edible vaccine could eventually prove to be a cost effective alternative to vaccines given by injection.

The study will require 15 to 20 volunteers to eat a raw potato containing DNA from Escherichia coli (E.coli), a pathogen than can be easily altered to carry and transmit other genetic material. Researchers expect the subjects who eat the potato to mount an immune response against a range of common bacterial and viral stomach infections. Researchers say the technology could potentially be used to prevent cholera, hepatitis B, dysentery, venereal disease and a variety of other gut infections common in developing countries. According to the World Health Organization, diarrheal diseases are leading causes of death among children under age 5 worldwide.

"That's why, right now, we're concentrating on the diarrheal virus and bacterial diseases," says Hugh Mason, Ph.D., one of the principle researchers at the Boyce Thompson Institute for Plant Research at Cornell University in Ithaca, N.Y., which developed the genetically engineered potato. Bananas, which are common in tropical climates and taste better than raw potatoes, are the next target for edible vaccine research.

Mason says the research will have wide applications, especially in developing countries where needle inoculations are time-consuming and costly. The trial's clinical component, where subjects will be recruited and the vaccine administered, will be led by the Center for Vaccine Development at the University of Maryland-Baltimore.

The human study is based on research at Texas A&M University in College Station, where researchers successfully immunized mice against E. coli by injecting diem with genetic material from tobacco plants bioengineered with a strain of E. coli DNA. The plant developed antibodies against the deadly pathogen, as did the mice, without developing any adverse symptoms.

Genetic engineering has been used for the last 15 years to vaccinate food crops against viruses and insect pests. Proponents say this technology cuts down on the need for pesticides, but critics argue that it warps natural growth patterns and will eventually devastate the plant's wild relatives.

Environmentalists and human-rights groups, as well as religious representatives, object on other grounds. They argue that genetic patenting, which allows corporations to purchase monopoly control of genetically altered plants or animals, violates the sanctity of life and will prevent therapeutic technologies from ever benefiting people who can't afford to pay. A patent application submitted by Cornell University for the edible human vaccine is pending with the U.S. Patent and Trade Office.