A transcutaneous immunization system delivers antigen to immune cells without
perforation
of the skin, and induces an immune response in an animal or human. The system uses
an adjuvant, preferably an ADP-ribosylating exotoxin, to induce an antigen-specific
immune response (e.g., humoral and/or cellular effectors) after transcutaneous
application of a formulation containing antigen and adjuvant to intact skin of
the animal or human. The efficiency of immunization may be enhanced by adding hydrating
agents (e.g., liposomes), penetration enhancers, or occlusive dressings to the
transcutaneous delivery system. This system may allow activation of Langerhans
cells in the skin, migration of the Langerhans cells to lymph nodes, and antigen presentation.