INTERLEUKINS | IL-15

Interleukin-15 (IL-15) is a 14–15 kDa protein that shares many biological activities with IL-2. IL-15 binds and signals via a trimetric receptor consisting of a common gamma chain, IL-2Rβ and IL-15Rα. Both IL-15 and IL-15Rα, which are essential for the high-affinity binding, have a much broader tissue distribution than IL-2/IL-2Rα. Multiple complex posttranscriptional regulatory mechanisms tightly control IL-15 expression. These findings suggest that IL-15 has pleiotropic functions in immune and nonimmune systems. It is possible that IL-15 has a role in respiratory diseases such as sarcoidosis and tuberculosis through its role in Th1-driven-inflammation.