Theoretically, scientists should be able to deliver antigens against E. coli, cholera, or other diarrhea-causing pathogens in just about any fruit or vegetable. But practicality may trump technology when it comes to picking how to package an edible vaccine.
The first human clinical trial featured raw potatoes (C.O. Tacket et al., Nature Medicine, 4:607-9, May 1998). The potatoes--which were engineered to express LT-B, an enzymatically inactive enterotoxin secreted by E. coli--were well tolerated and stimulated an immune response in volunteers. Tests showed that the transgenic vegetables created immune responses in both blood serum and the intestinal mucosa. However, the uncooked spuds also caused mild nausea in some subjects. And children, for whom these vaccines are being developed, may turn up their noses. "Clearly, raw potatoes are not very palatable to kids," notes Carol O. Tacket, a researcher at the University of Maryland School of Medicine's Center for Vaccine Development. Tacket, ...
