Source:http://linkedlifedata.com/resource/umls/id/C1333196
NCI: Cytokines are soluble glycoproteins released by cells of the immune system, which act nonenzymatically through specific receptors to regulate immune responses. Cytokines resemble hormones in that they act at low concentrations and bind with high affinity to a specific receptor. (Health On the Net Allergy Glossary; http://www.hon.ch/Library/Theme/Allergy/Glossary/allergy.html)