Epicyte Pharmaceutical Inc is working on a preventative treatment for HIV. But it isn't being concocted in a test tube. It's being cultivated in a stalk of corn

As an early entrant in the emerging field of plant-derived pharmaceuticals, privately held Epicyte uses its proprietary plantibodies technology to develop human monoclonal antibodies. The biopharmaceutical company said it is growing the first greenhouse plant lines to yield an antibody product that might potentially be used to prevent the transmission of HIV.

Kevin Whaley, Epicyte's director of antibody discovery, says the company's work is in the pre-clinical stage, which involves testing on primate models. It could be a year or two before the antibodies are tested on humans.

Epicyte will produce three different human antibodies -- called 2G12, 4E10 and 2FS -- in corn. Dow Chemical is a partner in the research, and the HIV plantibodies were developed with funds from the National Institutes of Health.

Epicyte officials say the antibodies work by binding HIV envelope proteins critical in the infectious pathway. It can be explained in simpler terms as enabling the antibodies to keep one step ahead of the pathogens, making the immune system more resistant to disease, Whaley said.

The corn used in Epicyte's research is really just a platform on which the antibodies can be produced. Maarten Chrispeels, director of the San Diego Center for Molecular Agriculture, says corn, soy, tobacco and certain aquatic plants can yield more proteins for less money than alternatives such as cultured animal cells.

Plant-derived pharmaceuticals are never intended to make it to the dinner plate, Chrispeels said.

Epicyte's Whaley, too, is quick to make the distinction between genetically modified foods and other plant-based sciences.

"This is not conventional agriculture, this is pharmaceutical manufacturing," Whaley said.

Epicyte's use of plants in drug discovery does present some unique regulatory constraints. Because crops are involved, Epicyte's work is monitored by the U.S. Department of Agriculture. And because drug candidates are involved, the U.S. Food and Drug Administration's Center for Drug Evaluation and Research must approve clinical trials and potential drug commercialization.

Epicyte's focus extends beyond HIV, to include the development of potential therapeutics for a variety of inflammatory and infectious diseases. Epicyte expects to be the first U.S. company to enter Phase I clinical trials of a human herpes antibody, called HX8, that was produced in plants.

Chrispeels says plant-derived pharmaceuticals are gaining attention and importance in the scientific community, especially as consumers have been slow to accept the concept of genetically modified foods.

He said that San Diego, in particular, has attracted plant biologists to public research institutions including the University of California, San Diego, the Salk Institute and The Scripps Research Institute, and companies including Diversa and Dow AgroSciences LLC, a subsidiary of Dow Chemical.

The Center for Molecular Agriculture, which operates as an organized research unit of UCSD, has seen enough interest in plant-derived pharmaceuticals to make it the topic of its October symposium, to be held at the Salk Institute. Epicyte is expected to be among the invited participants.