Interleukin 2 (IL-2) is a 15 kDa glycoprotein encoded by a single gene located in the q26-28 region of human chromosome 4. It is a type of cytokine signaling molecule in the immune system, regulating the activities of white blood cells (leukocytes, often lymphocytes) responsible for immunity. IL-2 is part of the body’s natural response to microbial infection, and in discriminating between foreign (“non-self”) and “self”. IL-2 mediates its effects by binding to IL-2 receptors, a complex consisting of three chains, termed α (CD25), β (CD122) and γ (CD132).
Monitoring of IL-2 levels in serum provides more detailed insights in several pathological situations such as cancer, infectious diseases, transplant rejection, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus and type I diabetes.