Production of Antibodies in Alfalfa (Medicago Sativa)

Abstract

Antibodies have long been recognized for their diagnostic and therapeutic potential. Advances in medicine and molecular biology, combined with the knowledge we will gather from the recent sequencing of the human genome, will pave the way to an even greater demand for antibody molecules. In order to satisfy this growing demand, alternative ways to current limiting production methods are being actively explored. Molecular farming of transgenic plants has gained a lot of attention in recent years as a promising large scale production and processing system. In this chapter, we will focus on a perennial legume crop, Medicago sativa (alfalfa), and its use in antibody production. Alfalfa benefits from several agronomic advantages such as nitrate fertilization-free cultivation, the existence of agricultural infrastructures and the possibility to rapidly produce clonal transgenic populations, making it a choice candidate for molecular farming purposes. Medicago’s molecular farming protocol comprises five steps. First, the gene encoding the protein of interest is inserted into alfalfa-specific expression vectors; second, the resulting constructs are transferred into alfalfa cells, followed by the regeneration of transgenic alfalfa plants. The transgenic population is then grown and harvested at the vegetative state. Finally, recombinant proteins are extracted from harvested leaves and purified, followed by the disposal of residual biomass. A case study illustrates the production in alfalfa of an IgG antibody identical to a monoclonal antibody produced in hybridomas. Strategies to improve antibody recovery and quality are discussed.