Seed-based expression strategies

Among the current molecular pharming approaches, seed-based expression offers particular advantages as heterologous proteins can be produced at high levels in a highly stable biomass that can also serve as an oral vaccine after either minimal or no processing. Therefore, seeds can be readily used as platforms for the production of low-cost vaccines that are environmentally friendly and easy to administer. In this chapter, various strategies that address expression of immunogens in seeds are presented. Seed-based approaches that have been undertaken to develop candidate vaccines against cholera, malaria, hepatitis B, and diarrhea are featured as examples of the promising potential of these approaches. Moreover, insights into the immunogenic properties of seed-based candidate vaccines are explored. In addition, efforts that prevent undesirable gene flow and release of transgene(s) into the environment are also explored.