Concepts in Mucosal Immunity and Mucosal Vaccines

Abstract

Currently, the majority of vaccines is administered parenterally by injection and is designed to induce protective immunity mainly through the induction of circulating antibodies. However, it is likely that some vaccines could be more effective if they were administered via mucosal routes. In contrast to parenteral delivery, mucosal immunization offers the possibility to induce immune responses directly at the sites where most pathogens initially infect. Hence, mucosal immunity could act as a first line of defense and, if systemic immunity is also present, could offer two layers of host protection. Moreover, needle-free vaccine administration has many potential additional advantages, including the potential to improve safety and increase patient compliance, with the potential for self-administration. Mucosal vaccine delivery is likely to progress over the next decade as the currently limited knowledge of the molecular mechanisms for the induction of mucosal immunity is expanded. A key challenge will be the design of efficacious and safe mucosal vaccines, with the stability of recombinant antigens after mucosal administration remaining a significant challenge. The combination of a broad panel of adjuvants and delivery technologies holds tremendous promise for effective, safe, needle-free vaccines, and the area is likely set for rapid advances over the next decade.