Intercellular adhesion molecules (ICAMs) are type I transmem brane glycoproteins, which contain 2-9 immunoglobulin-like C2-type domains, and bind to lymphocyte function- associated antigen-1 (LFA-1, also known as a L/ ß 2 or CD11a/CD18). ICAM-1 (CD54) binds to not only LFA-1 but also CD11b/CD18 (Mac-1) and CD11c/CD18. ICAM-1 is also the major receptor for human rhinovirus. ICAM-1 and LFA-1 are involved in the formation of the adhesion ring junction at the immunologic synapse between T cells and antigen presenting cells. ICAM-1 is expressed at low levels on diverse cell types, and is readily induced by activation with proinflammatory cytokines such as IL-1, TNF, IFN- γ , and GM-CSF. ICAM-1 plays a role in both adhesion and extravasation of leukocytes to endothelium during inflammation. Soluble forms of ICAM-1 (sICAM-1) have been detected in a variety of body fluids and correlated with the intensity of the clinical condition of inflammatory and immune disorders. Several studies have provided evidence that sICAM-1 can bind to cell surface ß 2 integrins (CD18), causing reduced adherence of leukocytes to endothelial cells and the accompanying intracellular signaling responses.Synonyms: ICAM-1, Intercellular adhesion molecule 1, Major Group Rhinovirus Receptor