Recombinant pharmaceutical protein production in plants: unraveling the therapeutic potential of molecular pharming

There is an increasing demand for the generation of recombinant pharmaceutical proteins for a wide array of therapeutic applications. In comparison to bacterial, yeast and animal cells, the production of recombinant proteins in plants with economic and therapeutic importance has only started recently. The most important prerequisite of any expression systems is that it should be simple and inexpensive. In this regard, plant-based expression has emerged an as accepted alternative to conventional expression platforms due to economic feasibility, rapid scalability, higher stability of recombinant proteins, safety due to lack of harmful substances (human, animal pathogens and pyrogens) and capability of producing proteins with desired secondary modifications. Heterologous expression using plants has played a pivotal role in the development of a myriad of recombinant proteins, including neutraceuticals and monoclonal antibodies being utilized in various therapeutic approaches. This paper presents an overview about the current status, various strategies and advantages of pharmaceutical protein production in plant expression systems. We also present a summary of expression of therapeutic monoclonal antibodies, vaccines, clinical trials and the regulatory aspects of plant-based expression. Furthermore, the challenges encountered in plant expression such as costs associated with existing purification strategies are discussed.