Monoclonal Antibodies from Tobacco Plants

Researchers are using tobacco plants to produce cancer-fighting monoclonal antibodies that recognize and hunt down breast and colorectal cancer cells.

While therapeutic applications for such antibodies continue to grow at a fast rate, production cannot keep pace. Hilary Koprowski, M.D., a virologist and professor of cancer biology at Jefferson Medical College of Thomas Jefferson University and Jefferson's Kimmel Cancer Center (Philadelphia, USA), argued that "plants are safer, less expensive, and easier to use” than currently used methods in the laboratory and with animals. For mass production purposes, he stated, "plants make more sense.” He and coworkers reported their findings in the May 23, 2006, issue of the journal Proceedings of the [U.S.] National Academy of Sciences.

In the most recent studies, Dr. Koprowski and his team inserted DNA coding for an antibody against the Lewis Y antigen, which is found on breast and colorectal cancer cells, among other cancers, into tobacco plants. The plants then become factories generating antibodies. As in earlier studies, the antibodies were able to kill the cancer cells in the laboratory and suppressed tumor growth in mice. Not only that, these plant-made antibodies performed as well as those produced in the conventional way, by mammalian cells. Both types of antibodies suppressed tumor cell growth in mice up to 28 days.

This study produced an added surprise, which has not been shown before: the researchers demonstrated that the antibodies attached to the human Fc receptor, a major step in the development of immunotherapy. So-called effector cells--tumor-cell killing macrophages--recognize monoclonal antibodies through their Fc receptors.

"This technology has all the potential in the world,” Dr. Koprowski said, adding that clinical trials involving plant-produced antibodies should be planned. "It will be the future, and in the next five to 10 years, it could be the main way that therapeutic antibodies are made.”



Related Links:
Jefferson's Kimmel Cancer Center