Plants Could Deliver HIV Vaccine in the Future, Researchers Say
Researchers are working on packing HIV-suppressing proteins into spinach as "the first step in the use of plants as a cheap, safe method of delivering AIDS vaccines," Reuters Health reports. The idea of using plant "factories" to fight disease has been investigated before, but Dr. Alexander Karasev of Thomas Jefferson University and his team, who presented the research at the annual meeting of the American Society for Microbiology in Orlando, are some of the first to focus on HIV. Karasev's team has been researching "tat," a protein that helps HIV reproduce within cells while also suppressing the human immune system, making it "an ideal target" for developing a preventive vaccine and treating those already living with HIV. They introduced a gene expressing the HIV tat protein into a common plant virus and "infected" spinach with the virus. The plant then began to work as a "factory" for producing tat. Using plants to produce and deliver a vaccine could reduce the manufacturing cost because vaccines grown in plants are cheaper to harvest than those produced in the lab, creating a "particular benefit" for developing nations where "logistics make vaccine production and delivery impractical," Karasev told Reuters Health. He added, "[T]here's a second issue, which is probably even more important -- safety. Whatever is produced in terms of vaccine components in animal cultures, or sometimes even in human tissue cultures, carries the remote possibility of contamination," and plant-based vaccines greatly reduce the risk of contamination. Karasev said he hoped that the human immune response can be "primed" to recognize HIV using this method in the same way that the plant-based delivery of a rabies vaccine works, but he noted that HIV "remains a complex adversary," and that "nobody knows which particular gene will be the best candidate for vaccination." But if researchers "can extract several different proteins of HIV from the same plant, it may help to create a combined vaccine," he added. Karasev said, "The ideal situation would be a prescription for a bowl of spinach," adding that the spinach was not genetically modified and "looks fine and tastes fine." To address variance in eating patterns, the team is looking into whether the plants can be dried, stored and made into special tablets (Mundell, Reuters Health, 5/22).This is part of the KHN Morning Briefing, a summary of health policy coverage from major news organizations. Sign up for an email subscription.