Molecular Pharming: Plant-Made Vaccines

Research on the use of plants for the production of vaccine antigens has increased greatly since the seminal studies published in the early 1990s. The initial strategy focused on oral delivery of minimally processed edible material from stably transgenic plants. Although substantial regulatory concerns exist regarding the use of food crops for vaccine production, the potential for vaccines expressed in seeds of corn and rice is especially promising. However, more recent development of robust transient expression systems greatly improved the potential to use plants for expression purification of recombinant antigens for more typical injectable delivery. Significant industrial development of methods for production of plant-made vaccines rapidly and at large-scale demonstrates the exciting capabilities of the technology. Notably, transient expression in leaves of Nicotiana benthamiana shows great potential for the production of several vaccines for human viral pathogens. Future work will address issues of processing plant material for optimal oral or parenteral delivery.