Figure 3.
Role of Th17 cytokines in immune homeostasis in the intestine, lung and skin. Although the interface tissues of the intestine, airways of the lung, and skin are charged with different functional roles, each is a major portal for pathogenic microbes and exists at homeostasis with a resident microbiota that is acquired shortly after birth. Accordingly, there are shared defensive strategies for partitioning microbes to the “outside” environment, and in each tissue robust innate immune mechanisms are reinforced by a propensity for development of Th17 pathway cells that reside in close apposition to the epithelial barriers of each site (see text for details).