Intramuscular delivery of a cholera DNA vaccine primes both systemic and mucosal protective antibody responses against cholera

Cholera is a potentially lethal diarrhea disease caused by the gram-negative bacterium Vibrio cholerae. The need for an effective cholera vaccine is clearly indicated but the challenges of eliciting both systemic and mucosal immune responses remains a significant challenge. In the current report, we discovered that a DNA vaccine expressing a protective cholera antigen, cholera toxin B subunit (CTB), delivered parenterally can elicit both systemic and mucosal anti-CTB antibody responses in mice. The priming effect by DNA immunization was demonstrated by higher mucosal antibody responses following one boost with the inactivated cholera vaccine (KWC-B) delivered orally when compared to the twice oral administration of KWC-B alone. This finding indicates that DNA vaccines delivered parenterally are effective in eliciting mucosal protective immune responses—a unique advantage for DNA vaccination that has not yet been well realized and should bring value to the development of novel vaccination approaches against mucosally transmitted diseases.