Cytokines
Cells of the immune system communicate with one another by releasing and responding to chemical messengers called cytokines. These proteins are secreted by immune cells and act on other cells to coordinate appropriate immune responses. Cytokines include a diverse assortment of interleukins, interferons, and growth factors.
Some cytokines are chemical switches that turn certain immune cell types on and off. One cytokine, interleukin 2 (IL-2), triggers the immune system to produce T cells. IL-2’s immunity-boosting properties have traditionally made it a promising treatment for several illnesses. Clinical studies are underway to test its benefits in diseases such as cancer, hepatitis C, and HIV infection and AIDS. Scientists are studying other cytokines to see whether they can also be used to treat diseases.
One group of cytokines chemically attracts specific cell types. These so-called chemokines are released by cells at a site of injury or infection and call other immune cells to the region to help repair the damage or fight off the invader. Chemokines often play a key role in inflammation and are a promising target for new drugs to help regulate immune responses.
Cytokines include lymphokines, produced by lymphocytes, and monokines, made by monocytes and macrophages. Credit: NIAID.
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