Interleukin-12 is a naturally occurring protein essential for the proper functioning of the human immune system.
Having either too much or too little interleukin-12 may play a role in the development of many diseases, including some cancers and auto-immune disorders like Crohn's, psoriasis, and rheumatoid arthritis. In turn, modulating interleukin-12 levels could yield new therapies for those conditions.
In an effort to create a new and cost-effective method for producing interleukin-12 and make more of the scarce protein available for research and therapeutic development, a team of scientists at Worcester Polytechnic Institute's Life Sciences and Bioengineering Center (WPI) and the Arkansas Bioscience Institute at Arkansas State University (ABI) reports that hairy roots from genetically modified tobacco plants can be grown in a contained novel mist bioreactor system, yielding significant quantities of murine interleukin-12. A paper detailing the results of the study has been published early, online, by the journal Biotechnology and Bioengineering and will appear in the journal's printed edition early in 2009.
"We are very encouraged by the results of this study," says Pamela J. Weathers, PhD, professor of biology and biotechnology at WPI, co-author of the paper. "Interluekin-12 is a valuable protein and there just isn't enough available for biomedical research, let alone for therapeutic development. Our study shows that we can use plants to produce interleukin-12, and other therapeutic proteins, in a cost-effective controlled process."
The tobacco project is one of several emerging collaborative efforts between WPI and ABI. In the current study, tobacco plants were modified in the lab of Carole Cramer, PhD, ABI's executive director and co-author of the paper. Cramer's team successfully inserted into tobacco plants a mouse gene that directs the production of interleukin 12. Hairy root cultures from those modified tobacco plants were then grown in a mist reactor developed in the Weathers lab. As its name implies, the mist reactor uses ultrasonic technology to spray a fine mist of water and nutrients on the root cultures, which are suspended in a plastic bag. The nutrient solution is collected at the bottom of the bag and recycled through the system. In this way, all of the materials are completely contained and isolated from the environment.
"Some have concerns about growing genetically modified plants in an open field where they could cross-pollinate with other species. Our mist reactor overcomes those concerns because the system is completely contained," Weathers says. "There is no interaction with the environment, and once we've collected the therapeutic proteins grown in the roots, all the remaining material is safely destroyed."