The IL-15 receptor alpha subunit (IL-15Rα) mediates high-affinity binding of IL-15, a pleiotropic cytokine implicated in the development of innate immune cells. We have generated IL-15Rα null (IL-15Rα(-/-)) mice to understand the role of IL-15Rα in immune development and function. IL- 15Rα(-/-) mice are markedly lymphopenic despite grossly normal T and B lymphocyte development. This lymphopenia is due to decreased proliferation and decreased homing of IL-15Rα(-/-) lymphocytes to peripheral lymph nodes. These mice are also deficient in natural killer cells, natural killer T cells, CD8+ T lymphocytes, and TCRγδ intraepithelial lymphocytes. In addition, memory phenotype CD8+ T cells are selectively reduced in number. Thus, IL-15Rα has pleiotropic roles in immune development and function, including the positive maintenance of lymphocyte homeostasis.
Lodolce, J. P., Boone, D. L., Chai, S., Swain, R. E., Dassopoulos, T., Trettin, S., & Ma, A. (1998). IL-15 receptor maintains lymphoid homeostasis by supporting lymphocyte homing and proliferation. Immunity, 9(5), 669–676. https://doi.org/10.1016/S1074-7613(00)80664-0