Clinical trials conducted by ProdiGene, a biopharmaceutical company in College Station, Texas, have demonstrated for the  first time that an oral vaccine expressed in plants gives protection against a virulent viral pathogen in livestock. The trials were conducted on swine using an edible form of a vaccine for transmissible gastroenteritis virus (TGEV).

"Protection from TGEV proves that this technology is an innovative method to address animal and human health at a time when fewer therapeutics, such as antibiotics, are available,'' said Joe Jilka, Ph.D., ProdiGene vice president of product development.

"Edible vaccines will give pork producers several distinct benefits,'' Dr. Jilka said. "Because the vaccines are fed instead of injected, they are not so labor-intensive. Meat quality would be improved, since there would not be a needle mark in the carcass. Other advantages are improved delivery of the antigen and potential for higher efficacy of mucosal disease vaccines.

"Perhaps the most important benefits are that edible vaccines will be less expensive and easier to administer,'' Jilka said. "Feeding a vaccine is much less stressful to the animal.''

"The potential of this technology could be very important to the swine industry, not just for vaccinating against TGE, but even for other diseases, especially intestinal,'' said Richard E. Mock, M.S., Ph.D., head veterinary virologist, Texas A&M Veterinary Medical Diagnostic Laboratory.

"Value is added to both livestock producers and grain farmers who will contract to grow the grain-based vaccines,'' said Dan Hammes, ProdiGene vice president of operations, who added that the preliminary trials used corn enhanced to create the protein that stimulates the TGEV antibody.

Swine TGEV can potentially be a major cause of sickness and death in young pigs, particularly in areas with high concentrations of pork production. It is a highly contagious disease that causes high mortality in pigs less than two weeks of age.

"These trials proved that we could deliver the antigen in edible form to an economically important animal and see protection in the animal,'' Dr. Jilka said. "Now, our work will focus on how much corn to deliver and the correct level of concentration.''

The trials were conducted using standard protocol for evaluating vaccine efficacy. "The results clearly showed that pigs respond to TGEV antigens expressed in the genetically-enhanced corn,'' Dr. Jilka said.

"The edible vaccine for swine TGEV is just the first of many innovative products from this technology,'' said Robert Dose, ProdiGene vice president for business development. "We are in discussions with several members of the animal health industry to target future products for other diseases.

"We are dedicated to the future of this technology and have more products in the pipeline for both animal and human healthcare applications,'' Dose said.

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 new field. 

Company news release
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