Vaccines for humans and animals that can be eaten, rather than injected, may become commonplace thanks to technology recently patented by ProdiGene, a biotechnology company located in College Station, Texas.

The patent covers viral disease vaccines - for Hepatitis and Transmissible Gastroenteritis Virus -
produced in genetically-enhanced plants. The vaccines produced using this technology can be
marketed either in edible form, made from parts of a fruit, vegetable or grain plant, or in injectable
form.

Hepatitis is a serious disease that annually infects millions of people worldwide. Transmissible
Gastroenteritis Virus is a highly infectious disease in swine and is particularly deadly in young pigs.

"We are excited about the edible vaccine technology because it has implications for worldwide
health,'' said ProdiGene President John A. Howard, Ph.D. "Many vaccines are too expensive for
some countries to offer widely to their human and animal populations.

"Edible vaccines have several advantages,'' Dr. Howard said. "They will be less expensive to
manufacture, they may not require a health care professional to administer, and they will not require refrigeration prior to use. These advantages will bring vaccines to many more people.''

"For centuries, plants have had a traditional role as a source of natural medicines, and now it is
possible to genetically enhance them to produce vaccines,'' said Jose Luis Di Fabio, Ph.D.,
program coordinator for vaccine technology access, Pan American Health Organization. "A wide
variety of new vaccines can become available that are inexpensive, easily administered and capable of being stored and transported without refrigeration.

"This new technology will contribute to global vaccine programs and will have a dramatic impact
on health care in developing countries,'' Dr. Di Fabio said. "And it will always be easier to
convince a child - even an adult - to eat a fresh fruit salad or granola bar, rather than receive
multiple shots for protection against several diseases.''

Most oral or edible vaccines have been cost-prohibitive in the past because the Food and Drug
Administration required such stringent purification. But the ProdiGene edible vaccines would be
grown in plants that are typically included in the diets of humans and animals; so this method would avoid the time and expense involved in purification and would result in more cost- effective
vaccines that are easier to administer.

"Plant-based vaccines are an exciting and novel new strategy for the development of oral vaccines. These vaccines may be very safe and inexpensive to produce and deliver to target populations,'' said Carol O. Tacket, M.D. of the Center for Vaccines Development at the University of Maryland.

Another advantage of this new technology is that multiple vaccines can be produced in one plant.
For example, there are several types of Hepatitis, each requiring a different vaccine. Through this
technology, plants could be grown that, when eaten, would vaccinate a person against all types at once.

Clinical trials for the Transmissible Gastroenteritis Virus vaccines are in progress now, and
ProdiGene officials expect clinical trials for Hepatitis B to begin soon.

ProdiGene, headquartered in College Station, Texas, is a biotechnology company that is
developing numerous industrial and pharmaceutical proteins from plants. The company was the
world's first to successfully commercialize recombinant proteins from genetically-enhanced plants. ProdiGene holds a series of patents and has the commercial expertise that provides it with a leadership position in this exciting new field.

Company news release
N1996