The mucosa represents the primary target site and thus the first barrier for most microbial
pathogens. Nevertheless, nearly all present-day vaccines are applied by an invasive route,
target the systemic immune system, and do not confer efficient mucosal protection. Currently,
mucosal immunity can only be achieved by the delivery of antigens via the mucosal route.
Therefore, multiple efforts are under way to develop mucosal vaccines and particularly live
oral vaccines as these would confer considerable advantages. We have engineered the …