CD106 is a 110 kD single chain type I glycoprotein also known as VCAM-1 and INCAM-110. It is expressed predominantly on activated vascular endothelium but has also been identified on follicular and interfollicular dendritic cells, some macrophages, bone marrow stromal cells, and non-vascular cell populations within joints, kidney, muscle, heart, placenta, and brain. Expression on endothelial cells as well as many other cells is induced by inflammatory stimuli and cytokines. Activated endothelial cells can release soluble forms of CD106 which can be detected in the blood. CD106 binds the integrins CD49d/CD29 (VLA-4) and alpha4beta7 that contribute to leukocyte adhesion, transmigration, and co-stimulation of T cell proliferation.