Successful human trial of potato hepatitis B vaccine

Genetically modified potatoes prevent Hepatitis B (rethink Science report)

American scientists have developed a genetically modified potato that may act as a hepatitis B vaccine, which is good news for developing countries.

The hepatitis B virus invades the liver and kills about 500000 people every year. But traditional vaccines need to be refrigerated, which is difficult to do in remote areas of developing countries with warm climates. Medical workers often have to struggle to judge whether the expensive hepatitis B vaccine fails due to accidental heat during transportation.

To that end, CharlesArntzen, a biologist at the University of Arizona in the United States, and his colleagues designed an edible vaccine that does not need to be refrigerated-potatoes. They took a gene from the hepatitis B virus and implanted it into a potato plant, which produced the virus antigen. After people eat this potato, the antigen protein will trigger the body's immune response against the hepatitis B virus.

Although this method is unlikely to replace the initial vaccination, it could replace repeated injections that maintain immunity later, the team said. "it has the potential to have a significant impact on global health," said JulianMa, an immunologist at St. George's Hospital School of Medicine in London.

Super potato

In trials conducted by Arntzen and his colleagues with the genetically modified potatoes, participants had received their first hepatitis B vaccine in the past 1 to 15 years. The results showed that 19 of the 33 participants produced more hepatitis B antibodies after eating potatoes, and one of them had a 56-fold increase in antibody levels. The report is published in the Proceedings of the National Academy of Sciences (PNAS).

The potato vaccine works on 60% of participants, which is good news.

The process of making progress.

The Arntzen team has combined two other vaccines into potatoes, one against traveling diarrhea caused by E. coli and one against intestinal flu caused by Norwalk factor.

"We are very happy," Arntzen said. "there are always skeptics who say it won't work, but we have solved all these problems." Unlike E. coli and Norwalk factor, the hepatitis B virus has not evolved to survive in the intestines, so the success of the new vaccine is particularly surprising: if the hepatitis B vaccine in potatoes is to work on the immune system, it must first pass the test of the digestive tract.

However, raw potatoes are not an appetizing food, and the amount of vaccine in them is not stable. To that end, Arntzen and colleagues are focusing on genetically modified tomatoes containing vaccines and trying to turn them into pills. "I hope we no longer need to use untreated materials for human clinical trials," he said. "