The future of mucosal immunology: studying an integrated system-wide organ

The term 'common mucosal immunological system' was coined by John Bienenstock nearly 40 years ago. He suggested the concept when the bronchus-associated lymphoid tissues his group described were found to be similar to those in the gastrointestinal tract. Ironically, appreciation of the importance of this term is only now truly beginning. Since then, the mucosal immune system has received a great deal of attention and is described as an integrated network of tissues, cells and effector molecules that protect the host from infection and environmental insult at mucous membrane surfaces. Mucosal surfaces are immunologically unique, as they act as the primary interface between the host and the physical environment yet also have key barrier functions. It has become increasingly evident that mucosal surfaces are also the main sites of interaction between the host and its associated commensal microbial community. In the past 40 years, the field of mucosal immunology research has exploded and understanding of this key component of the immune system has flourished. Many important findings have come from this research and have aided in the understanding of immune deficiencies and associated diseases and facilitated the design of effective vaccines. The next decade will be important in determining how the knowledge gained is synthesized and which directions future studies take.