Genetically modified tobacco plants to fight HIV?

U.K. researchers announce approval to launch the first human clinical trial of a genetically modified anti-HIV microbicide called P2G12, grown in Germany.

The production plant in Germany.

Drug companies have long used plants to produce pharmaceuticals--and tobacco plants, perhaps ironically, have been explored for their potential role in fighting such things as cancer, cavities, scorpion venom, and more.

The latest big news, announced at a press conference in London this morning, is that U.K. regulators have, for the first time, approved a human clinical trial of a monoclonal antibody produced using genetically modified tobacco plants.

Monoclonal antibodies are made from identical immune cells that have been cloned from a unique parent cell to fulfill a specific role. The roots of this idea, which date back more than 100 years, helped German scientist Paul Ehrlich win a Nobel Prize in 1908 for work that ultimately resulted in an effective syphilis treatment.

But using tobacco plants that have been modified to stop the transmission of HIV is the culmination of a major 21st century project called Pharma-Planta, which was launched by a few dozen academic and industrial partners in 2004 with $17 million in funding from the European Union.

This initial trial in 11 participants will test the safety of the antibody, called P2G12, which is applied topically to the vaginal cavity and is thus specific to transmission to females. If it is proven to be safe, it will then be tested for effectiveness.

"This is a red-letter day for the field," Julian Ma, scientific coordinator for Pharma-Planta and professor of molecular immunology at St George's University of London, said in a statement. "The an acknowledgment that monoclonal antibodies can be made in plants to the same quality as those made using existing conventional production systems. That is something many people did not believe could be achieved."

Although the plants were grown in containment greenhouses by the Fraunhofer Institute for Molecular Biology and Applied Ecology in Germany, the consortium says one of the major advantages of using genetically modified plants to derive antibodies is that they can be grown in the very country that needs them, a boon for both the environment and local economies.

Such a boon could, of course, be a long way off. Fraunhofer custom-designed its processing plant to isolate and purify P2G12, a step that was both expensive and groundbreaking. In fact, the facility was the first of its kind to be granted a license to manufacture recombinant pharmaceutical products from plants in Europe.

Ultimately, the approval of clinical trials of P2G12 opens the door for trials of other plant-derived medicines that could treat a wide range of diseases.