Interleukin-2 (IL-2) is a type of protein known as a cytokine, which plays a crucial role in the immune system. It is primarily produced by T cells, a type of white blood cell, and helps regulate the growth, development, and activity of immune cells. IL-2 is essential for the proliferation of T cells and B cells, which are vital for the body’s defense against infections and diseases. In addition to its role in immune response, IL-2 is also used in medical treatments, particularly in cancer therapy. It can stimulate the immune system to attack cancer cells more effectively. Researchers are exploring its potential in treating various conditions, including autoimmune diseases and organ transplant rejection.