<s>[INST] # Interleukin 15
IL-15 is a glycoprotein with a structure similar to IL-2, but with different receptor interactions and biological functions. IL-15 has a significant role in the development, survival, and function of NK cells, but also has strong effects on T cells, particularly CD8+ T cells, promoting their survival, proliferation, and effector functions. IL-15 shares the IL-2Rβ and IL-2Rγ chains with IL-2, but it signals through a distinct receptor composed of IL-15Rα, IL-2Rβ, and IL-2Rγ subunits. What is the main function of IL-15 compared to IL-2?[/INST]