• Interleukin is the generic name for a group of well-characterized cytokines that are produced by leukocytes and other cell types. They have a broad spectrum of functional activities that regulate the activities and capabilities of a wide variety of cell types. They are particularly important as members of the cytokine networks that regulate inflammatory and immune responses.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• One of a group of related proteins made by leukocytes (white blood cells) and other cells in the body. ILs regulate immune responses. ILs made in the laboratory are used as biological response modifiers to boost the immune system in cancer therapy. An interleukin is a type of cytokine.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• A group of substances that act as messengers in the immune system.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• Soluble factors which stimulate growth-related activities of leukocytes as well as other cell types. They enhance cell proliferation and differentiation, DNA synthesis, secretion of other biologically active molecules and responses to immune and inflammatory stimuli.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• Interleukin (IL), any of a group of naturally occurring proteins that mediate communication between cells. Interleukins regulate cell growth, differentiation, and motility. They are particularly important in stimulating immune responses, such as inflammation. Interleukins are a subset of a larger...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020