By genetically modifying rice plants, scientists have created an edible vaccine that triggers an immune reaction capable of neutralizing cholera toxin, tests in mice show. But the researchers stress that the altered rice wouldn't be sold in stores, grown openly, or be eaten as food. Rather, they envision rice-powder capsules or pills that would deliver the vaccine.
The bacterium Vibrio cholerae spreads through contaminated drinking water. In the body, the microbe attaches to intestinal tissues and releases its toxin, which causes severe diarrhea. The ensuing dehydration can be fatal.
To fashion the new vaccine, immunologist Hiroshi Kiyono of the University of Tokyo and his colleagues engineered rice plants to make grains that contain a harmless fragment of the