| Popis: |
For immunological, economical, and logistical reasons, mucosal immunization is a desirable alternative to conventional parenteral vaccination strategies. However, mucosal surfaces are persistently exposed to environmental, microbial, and dietary antigens for which complex regulatory systems are in place to prevent the induction of effector adaptive immune responses. This tolerogenic environment poses a significant challenge to the development of subunit mucosal vaccines and consequently, mucosal immunization requires the use of immune-potentiating adjuvants and/or delivery systems as part of vaccine formulations. In addition, the action of proteolytic enzymes and the low pH of the stomach are major obstacles for oral vaccines in particular. Such barriers make the development of systems capable of maintaining antigen integrity a necessity for effective mucosal vaccines to come onstream. Advanced systems must be capable of protecting antigens, enhancing transepithelial uptake, and potentiating the immune response while being well-tolerated. While such systems remain elusive, nonliving particulate adjuvant formulations, such as microparticles, liposomes, and immune-stimulating complexes (ISCOMs) have demonstrated potential to enhance cellular and humoral immune responses to mucosally administered vaccines. This chapter will address the challenges facing the development of subunit mucosal vaccines and the potential of nonliving delivery systems to facilitate the generation of enhanced mucosal vaccine strategies. |
