Garden-variety vaccines: antigens derived from transgenic plants.

The discovery of new vaccines can result from deletion of virulence determinants from a specific pathogen or from identification of target antigens that stimulate a protective immune response. Vaccine development will become less empirical as applications of genomics, proteomics and reverse vaccinology are exploited, and new protective antigens will emerge for inclusion in the vaccines of the future. However, production and purification of these new antigens for oral and parenteral use using traditional expression systems, will be expensive and unattractive to vaccine manufacturers who see the vaccine market as economically uninviting. Cost is one of the persistent barriers to deployment of new vaccines to populations that need them most urgently. This factor will inhibit the development and distribution of safe and effective new vaccines against high priority pathogens.