Assembly of antibody in plants

Secretory antibodies are made up of 4 different proteins. To express these 4 foreign genes, and and therefore the complete secretory antibody, in a single plant, 4 separate plants can be generated each expressing one of the genes. These plants can then be sequentially crossed to generate progeny plants that accumulate the foreign genes. By the 4th generation, the plants will contain all 4 genes and make the complete secretory antibody.