The Interleukin-2 Receptor (IL-2R) is a protein found on the surface of certain immune cells, such as T cells. It plays a crucial role in the immune response by binding to Interleukin-2 (IL-2), a signaling molecule that promotes the growth and activation of these cells. IL-2R exists in three forms: alpha (CD25), beta (CD122), and gamma (CD132). The interaction between IL-2 and its receptor stimulates T cell proliferation and differentiation, which is essential for a robust immune response against infections and diseases, including cancer.