Shigella flexneri is a member of the Enterobactercea family and a common cause of fatal bacillary dysentery in undeveloped countries. There is currently great interest in developing an easily procured and inexpensive vaccine to alleviate this cause of dysentery. This experiment attempts to synthetically replicate the most antigenic parts of the OmpA gene of Shigella flexneri and produce it in plants for use as a vaccine. The OmpA protein is found on the outer membrane of S. flexneri and aids in cell growth, conjugation and allows bacteria to penetrate and infect a mammalian cell eliciting an immune response without an adjuvant agent. Software called "Antigenic"; was used to calculate the most antigenic amino acids of the OmpA protein. The highest two antigenic regions were synthesized as a single concatamer and placed into the PBI121 plant expression vector. My goal was to determine if this gene construct could produce the intended antigen in plant tissue. Tobacco was chosen because it is relatively easy to transform and culture. If successful, the next step will be to transform a more palatable plant, such as carrot.