Safety, Immunogenicity and Efficacy Study of Inactivated Whole Cell Shigella Flexneri 2a Vaccine With and Without dmLT in Adults

1. Healthy adults, male or female, age 18 to 45 years (inclusive) at the time of enrollment.
2. General good health, without clinically significant medical history, physical examination findings or clinical laboratory abnormalities per clinical judgment of PI.
3. Willingness to participate in the study after all aspects of the protocol have been explained and written informed consent obtained.
4. Completion of a training session and demonstrated comprehension of the protocol procedures and knowledge of Shigella associated illness by passing a written examination (70% pass score).
5. Availability for the study duration, including all planned follow-up visits.

Exclusion Criteria:

1. Presence of a significant medical or psychiatric condition that in the opinion of the investigator precludes participation in the study. Some medical conditions that are adequately treated and stable would not preclude entry into the study. These conditions might include stable asthma controlled with inhalers or mild hypertension stably controlled with a single agent.
2. Significant abnormalities in screening hematology, or serum chemistry as determined by PI or PI in consultation with the Medical Officer and sponsor.
3. Recent of a non-study vaccine or receipt of another investigational product (within 14 days before vaccination).
4. Have household contacts who are \<3 years old or >70 years old or infirm or immunocompromised (for reasons including corticosteroid therapy, HIV infection, cancer chemotherapy, or other chronic debilitating disease).
5. Use of any medication that affects the immune function (e.g., corticosteroids and others) within 30 days preceding the first vaccination or planned use during the active study period.
6. Symptoms of Traveler's diarrhea associated with travel to countries where Shigella or other enteric infections are endemic (most of the developing world) within 1 year prior to dosing.
7. History of shigellosis or Shigella vaccination or challenge or a laboratory worker with known exposure to Shigella within the last 6 months
8. Prior receipt of experimental Shigella vaccine or live Shigella challenge within 3 years.