Fig. 2

Principles of plasmid construction and flow chart of oral vaccine preparation. The image was drawn with the online software FIGDRAW 2.0. (https://www.figdraw.com/static/index.html#/).
Principles of plasmid construction and flow chart of oral vaccine preparation. The image was drawn with the online software FIGDRAW 2.0. (https://www.figdraw.com/static/index.html#/).