Tobacco plant be the key to HIV Prevention via Microbicidal Gel?

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Researchers from the University of Louisville will lead an international effort to utilize tobacco plants to develop a gel containing a specific protein that will prevent the transmission of HIV. The project is being funded by a five-year, $14.7 million grant from the National Institutes of Health.

Kenneth Palmer, PhD, is leading research into using tobacco plants to help develop a gel that would prevent HIV.


“Our researchers are looking to solve problems that affect the world,” James Ramsey, president of the University of Louisville, said during an announcement of the research Aug. 4. “Globally, more than 34 million people are HIV positive. The development of a low-cost method to prevent transmission of HIV certainly is something that is desperately needed and the use of tobacco plants as a method of carrying the vaccine appears to be key in the process.”

“Approximately seven years ago, UofL and Owensboro Health created a joint venture to develop a world-class plant pharmaceutical program that would have an impact globally,” said David L. Dunn, MD, executive vice president for health affairs at UofL. “Today’s announcement, coupled with the announcement we made in May about the Helmsley Charitable Trust providing funding to our research into two other cancer vaccines utilizing tobacco plants, demonstrates that the vision is becoming a reality.”

Kenneth Palmer, Ph.D., professor of pharmacology and toxicology and director of theOwensboro Cancer Research Program of UofL’s James Graham Brown Cancer Center, is leading a team of researchers from the University of Pittsburgh, the Magee-Women’s Research Institute in Pittsburgh, the Centers for Disease Control and Prevention, Karolinska Institutet in Stockholm, Sweden, the University of Manitoba in Winnipeg, Canada, the University of Maryland, Baltimore and Kentucky Bioprocessing Inc. and Intrucept Biomedicine LLC in Owensboro.

The team is working with the carbohydrate combining protein Griffithsin (GRFT), which is found in red algae. In laboratory work, the protein has shown to have broad-spectrum activity against HIV. GRFT binds to the dense shield of sugars that surrounds HIV cells and prevents these cells from entering other non-HIV cells. The team plans to develop a gel containing the protein for use during sexual intercourse by people at risk for HIV transmission.

To develop the microbicide, Palmer’s team takes a synthetic copy of the protein and injects it into a tobacco mosaic virus, which carries the protein into the tobacco leaves. After 12 days, the researchers harvest the leaves and extract the mass-produced protein for development into the vaccine.

“Our goal is to optimize the delivery system of the protective agent, which in this case is a gel, and determine its safety and estimates of its efficacy, leading to a first-in-humans clinical trial,” Palmer said.

“People may question why a cancer program is conducting research into HIV prevention,” said Donald Miller, MD, director of the James Graham Brown Cancer Center, a part of KentuckyOne Health. “In fact, cancer can be a result of every major disease that we know about, and HIV infection is no exception.”

Overall, the grant contains three significant projects – The Critical Path Project; Preclinical Testing Project; and Clinical Trial Project.

The critical path project involves manufacturing the microbicide active ingredient, ensuring quality of the microbicide and the formulated gel product and production for actual use. This process is in collaboration with two Owensboro-based biotechnology companies (Kentucky Bioprocessing Inc. and Intrucept Biomedicine LLC), and Lisa Rohan, PhD, at the University of Pittsburgh and Magee-Women’s Research Institute. Rohan has significant experience developing delivery systems for similar medications.

The preclinical testing project is a collaboration with the Centers for Disease Control and Prevention in Atlanta to use an animal model to ensure that the vaccine is safe and to determine that it actually provides protection from infection.

The clinical trial project involves developing the application to conduct a clinical trial for the Food and Drug Administration, as well as conducting the first-in-humans testing.