Plant-based vaccines: unique advantages.

Numerous studies have shown that viral epitopes and subunits of bacterial toxins can be expressed and correctly processed in transgenic plants. The recombinant proteins induce immune responses and have several benefits over current vaccine technologies, including increased safety, economy, stability, versatility and efficacy. Antigens expressed in corn are particularly advantageous since the seed can be produced in vast quantities and shipped over long distances at ambient temperature, potentially allowing global vaccination. We have expressed the B-subunit of Escherichia coli heat-labile enterotoxin and the spike protein of swine transmissible gastroenteritis virus at high levels in corn, and demonstrate that these antigens delivered in the seed elicit protective immune responses.