MadSci Network: Immunology |
What are cytokines and how do they work? Cytokines are a group of mostly soluble molecules (peptides and proteins) that mediate cell to cell communication and show their physiological effect in nano- to picomolar concentrations (which is very low). They comprise interleukins, chemokines, and other molecules such as growth factors. They can act as signals between all the different blood/immune cells (where they were first described in the 1960s), between nerve cells and blood/immune cells, and vice versa. Basically all cells that are involved in an immune response in some way or other (or the ones derived from blood cell precursors) will react to cytokines which in this case function as immune modulators and growth factors. Other cell types such as nerve cells, endothelial cells (the ones lining blood vessels), kidney cells, placental cells, etc., respond to cytokines as well. Cytokines are no homogeneous group of molecules but are grouped together because of their functional similarity. They can be subdivided into families based on structural similarities, e.g. the IL-1 family, the IL-6/LIF/oncostatin family, etc. Cytokines are involved in a) development, e.g. as so called hematopoietic factors that control the development of blood cell precursors into different kinds of blood and immune cells b) inflammation, e.g. pariodontitis (inflamed gums), allergies, autoimmune diseases, etc. c) physiological stress, e.g. in wound healing, fever, etc. d) other processes and ailments/diseases: osteoporosis and control of bone physiology in general, depression and other psychiatric disorders, anorexia, some disorders of the heart (not in love sickness though I am afraid) Cytokines work by specifically binding to their receptors which themselves can be subdivided into various families. Most receptors are multimers, i.e. they consist of two or more subunits (either identical or nonidentical), and some may require coreceptors to function. Upon binding the cytokine activates the receptor, and subsequently one of a number of signal transduction pathways is turned on, which eventually leads to a change in gene expression. References (there are tons of them dealing with the roles of cytokines in specific disorders or physiological processes but I selected some more general ones): 1. Curfs JH, Meis JF, Hoogkamp-Korstanje JA (1997). A primer on cytokines: sources, receptors, effects, and inducers. Clinical Microbiology Reviews 10(4):742-80 2. Holtmann H and Resch K (1995). Cytokines. Naturwissenschaften 82: 178 - 187. 3. Rosenbaum JT, Brito B, Han YB, Park J, Planck SR (1998). Cytokines. An overview. Advances in Experimental Medicine and Biology 438:441-6 Some selected online references: The Cytokine Homepage The Cytokine Web ABC News article on chronic pain in cancer and the possible role of cytokines I hope this answers your question. In case you have any more questions feel free to email me
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