Transgenic plants of Nicotiana tabacum L. express aglycosylated monoclonal antibody with antitumor activity

The expression and production of pharmaceutical, industrial and veterinary proteins in plants is an attractive approach. These expression hosts bear an enormous production potential in terms of volume, easy processing of the starting material, and safety of the fi nal product due to the lack of pathogens able to infect animal and human cells. Antibodies are among the most frequently proteins expressed in plants, subsequently called plantibodies. However, plantibodies are differently glycosylated in plant cells, with oligosaccharide residues being added which may them immunogenic in the fi nal organism. For that reason, several strategies have been developed to genetically modify host plants to mimic the N-glycosylation patterns typical in animal cells. This work was aimed at developing a strategy to obtain a aglycosylated plantibody version of nimotuzumab, the fi rst antibody registered as a product in Cuba for cancer immunotherapy. The strategy comprised the genetic modifi cation of the heavy chain glycosylation site of nimotuzumab, and its expression as an aglycosylated protein in tobacco leaves, by means of developing a transient expression system using Agrobacterium infi ltration into tobacco leaves for the initial characterization of the plantibody. It was demonstrated that transgenic plants were capable of producing a plant-derived nimotuzumab antibody which retained the antitumor activity in vitro and in vivo, compared to its glycosylated counterpart produced in mammalian cells. This work demonstrates the potential of transgenic plants to produce aglycosylated therapeutic antibodies for cancer treatment, and won the National Award of the Academy of Sciences of Cuba in 2012.