Expression and assembly of a full-length monoclonal antibody in plants using a plant virus vector

We have used a tobacco mosaic virus-based vector to express monoclonal antibody (mAb) CO17-1A, directed to a colon cancer antigen, in plants. Genes encoding heavy and light chains of this antibody were introduced independently into the tobacco mosaic virus vector. Upon co-infection of Nicotiana benthamiana plants with both recombinant virus constructs, genes for heavy and light chains were expressed and assembled into a full-length antibody. A functional plant-expressed antibody was detected by ELISA and immunoblot in extracts from systemically infected leaves. This is the first report on the use of a plant virus vector to express and assemble a full-size antibody.