Immunomodulators and delivery systems for vaccination by mucosal routes

Current paediatric immunization programmes include too many injections in t he first months of life. Oral or nasal vaccine delivery eliminates the requ irement for needles and can induce immunity at the site of infection. Howev er, protein antigens are poorly immunogenic when so delivered and can induc e tolerance. Novel ways to enhance immune responses to protein or polysacch aride antigens have opened up new possibilities for the design of effective mucosal vaccines. Here, we discuss the immunological principles underlying mucosal vaccine development and review the application of immunomodulatory molecules and delivery systems to the selective enhancement of protective immune responses at mucosal surfaces.