In5tranasal vaccination of humans - adjuvants and mechanisms

摘要

The development of new subunit/DNA vaccines, mucosal vaccination and the development of new vaccine delivery systems are three of the fastest growing areas within vaccinology. The mucosa is constantly exposed to antigens of microbial, environmental or food origin and requires an effective defence system to fulfil necessary immunological protection. It covers over 400 m~2 in humans and the cellular mass exceeds far the total lymphoid cells found in the bone marrow, thymus, spleen and lymph nodes combined. This system differs in several fundamental ways from the systemic lymphoid system. It does not undergo any age-associated dysfunction and an immune response originating at one mucosal surface is able to induce a strong immune response at most distant mucosal surfaces. The mucosal immune system consists of both T (and Th cells) and IgA precursor B cells, where the production of IgA is actively transported across the epithelia, entering the mucus lumen. These cells transit and are distributed throughout the mucosal tissues, they are able to induce selective accumulation in mucosal effector sites when immune defence is required. Excipients, such as immunological adjuvants, may be used to direct these cells to those areas where they are needed as well as directing the response to either humoral- or cell-mediated immune response.