Expression of a vaccine protein in a plant cell line using a geminivirus-based replicon system.

Edible vaccines have been generated from both transgenic plants as well as from plant viral vectors. Here, we have taken the best attributions of both systems and designed a minimalized version of the bean yellow dwarf geminivirus (BeYDV)-based replicon consisting of the cis-acting elements required for BeYDV replication as a means to express foreign genes in a plant cell line. Replication can be switched on at high levels upon expression of the BeYDV Rep protein, and gene expression enhanced enormously. Construction of an expression cassette encoding a synthetic vaccine gene and analysis of expression levels of a vaccine protein in a plant cell line system are described.