Lymphokines are proteins released by white blood cells that typically deliver information to other immune cells. Binding to the surface of different types of cells, the proteins can trigger them to grow; activate in the case of an infection; eliminate parasites, viruses, and fungi; or destroy other cells. Lymphokines and cytokines generally belong to a class of substances that regulate immune responses. They can influence the function of several different types of cells that fight off infections and disease in the body.
The effect of lymphokines on the immune system sometimes triggers a cascade of reactions that lead to inflammation. Antibody-producing cells can be activated, so the proteins often have an effect on allergic reactions as well as direct other disease-killing cells to the right areas. There are different kinds of lymphokines. These include substances called interleukins that stimulate certain immune cells to grow, as well as tumor necrosis factor, which can target and eliminate cells that are diseased, kill the ones that become cancerous, and eradicate viruses and other intruders.
A lymphokine called interleukin-1 is released by macrophages, or immune system cells that consume foreign substances. It can trigger different effects and sometimes results in food allergies, but typically leads to the production of more cells to fight infections. Interferon is another variety of the lymphokines that can suppress virus production. It was one of the first class of cytokines that researchers discovered. Other kinds can differentiate immune cells as they mature; one type of interleukin even regulates how immature precursor cells develop.
White blood cells that circulate in the blood are sensitive enough to detect small numbers of lymphokines. These cells can move to where more of the proteins are, while stimulating other responses along the way. Like other cytokines, the protein messengers can each be involved in various functions, even ones that are generally attributed to other substances. There are some, in fact, that are often involved in the same process, like stimulating immune cell activity in localized areas, for example.
Lymphokine research is often included in clinical trials for many diseases that affect the immune system, including Acquired Immune Deficiency Syndrome (AIDS) as well as some types of cancer. Also used in patients receiving organ and bone marrow transplants, lymphokines are sometimes used as part of individual or combined therapies. There are many types of proteins that signal the immune system and, since certain ones can perform multiple functions, it is often difficult to predict treatment outcomes.