Integrin beta-2 (CD18) is a protein that in humans is encoded by the ITGB2 gene. Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain. Integrins are known to participate in cell adhesion as well as cell-surface mediated signalling. In humans lack of CD18 causes Leukocyte Adhesion Deficiency, a disease defined by a lack of leukocyte extravasation from blood into tissues. The beta 2 integrins have also been found in a soluble form. Signals transduced by integrins play a role in many biological processes, including cell growth, differentiation, migration and apoptosis.
