By Mark Greener

Genetically engineered potatoes expressing hepatitis B surface antigen boost immunity, according to a paper published in Proceedings of the National Academy of Science.

The double-blind clinical trial enrolled 42 adults who responded previously to an injectable vaccine. Serum antibodies increased in 62.5% of those who ate three doses of the genetically engineered booster vaccine and in 52.9% who ate two doses. Anti-HBs titers increased up to 56-fold and up to 30-fold respectively. Anti-HBs titers did not increase in volunteers who ate non-engineered potatoes. The vaccine, which uses only one viral protein, might be safer than oral vaccines using weakened living viruses, the researchers comment.

“We envisage that the final formulation will be a transgenic plant that will be handled via processing technologies and made up into a final formulation of known dosage for oral delivery, perhaps as a powder in a capsule,” lead author Yasmin Thanavala, from Roswell Park Cancer Institute, Buffalo said. “It would be very useful in developing countries to have an oral vaccine without the inherent problems associated with the reuse of needles and syringes.”