Defending the mucosa: adjuvant and carrier formulations for mucosal immunity

A majority of infectious microorganisms either colonize or cross mucosal surfaces to enter the host. A major goal in vaccine design is to induce a protective, lasting immune response against potential pathogens at mucosal surfaces. In addition, mucosal vaccines can offer needle-free delivery, thereby improving accessibility, safety, and cost-effectiveness. Challenges to successful mucosal vaccination include poor induction of mucosal immunity, limited understanding of protective mechanisms and crosstalk between mucosal compartments, and the availability of safe, effective mucosal adjuvants and delivery systems. This review focuses on some key advances in the field of mucosal vaccinology within the past 2–3 years, including reports on promising new formulations and investigations into the mechanisms of established mucosal adjuvants and/or particulate carrier systems.

► Mucosal surfaces are the most common sites of pathogen colonization or entry.
► Mucosal vaccines may offer improved efficacy, safety, and accessibility.
► Vaccine formulation with an adjuvant or particulate carrier can promote mucosal immunity.
► We review key advances in mucosal vaccinology within the past 2–3 years.