The mucosal immune system is a very important component of the body's defence against pathogenic organisms, especially those responsible for enteric infections.On the basis of the concept of a common mucosal immune system, there is currently much interest in the possibility of developing oral vaccines against respiratory and urogenital tracts infections.There is also a great need to develop strategies for enhancing delivery of antigens to the mucosal immune system as well as to identifymucosa-active immunostimulating adjuvants.