Gut as the largest immunologic tissue.

The host is continuously exposed to the environment via the mucosal surface. To this end, a large number of infectious agents, allergens and foreign proteins enter the inside of our bodies via the oral region, nasal and upper respiratory tracts, intestine and reproductive tract. The total area of these mucosal surfaces, which cover these tube-like tissues are at least two hundred times larger than those of skin. To provide an optimal first line of defense for these large surface areas, the mucosal immune system including secretory immunoglobulin A (S-IgA), mucosal alphabeta and gammadelta T-cells and epithelium play an essential role. The goal of our research is aimed at understanding the molecular and cellular aspects of the mucosal immune system and their defense against infectious diseases, inflammation and immunological disorders. Further, it is important to quickly apply our fundamental findings of the mucosal immune system to the development of mucosal vaccines.