The synthesis of selected antigens in plants and their oral delivery has great potential for reducing the costs of vaccine production and administration. The application of this technology requires antigen concentrations in final plant material to be uniform to ensure consistent dosing. In addition, antigen levels should be such as to allow the volume of each dose, containing a set amount of antigen, to be practical for oral delivery. Here, we demonstrate that the Lt-B protein of enterotoxigenic E. coli is evenly distributed in defatted corn germ prepared from transgenic grain. Furthermore, the choice of sub-cellular location for Lt-B affects accumulation of the protein in excess of four orders of magnitude.