Tobacco Making Human-Like Antibodies

Numerous studies have demonstrated the feasibility of plants as hosts for the cost efficient production of pharmaceutical proteins such as monoclonal antibodies. Scientists can now produce large quantities of monoclonal antibodies, up to 500 mg/kg leaf, using virus-based transient expression systems. However, most pharmaceutical proteins are complex proteins that require post-translational modification for biological activity. Some proteins need to be sugar coated, or be glycosylated, to function correctly. The sugar coating, or N-glycans, produced by plant cells are quite different from those produced by animal cells. These differences currently limit the commercial production of glycosylated plant-made pharmaceuticals.

A group of researchers from France and Canada has developed a way to ‘humanize' the structure of plant N-glycans in tobacco by silencing the activity of some plant enzymes and transient co-expression of a chimaeric human β1,4-galactosyltransferase, an enzyme that plays a pivotal role in the glycosylation process in mammalian cells. The approach employed by the scientists did not only result in the production of antibodies with ideal N-glycans structure but recombinant antibodies were produced as well at levels reaching 1.5 g/kg fresh weight, 100 percent higher compared to similar studies.

The paper published by Plant Biotechnology Journal is available at http://dx.doi.org/10.1111/j.1467-7652.2009.00414.x