Clone MRα4-1 recognizes the mouse CD49d antigen, a 150 kDa integrin family member, also known as integrin α4 chain or VLA-4α chain. Integrins are cell-surface receptors, expressed as heterodimers essential in various processes mediating intercellular or cell-matrix interaction. CD49d associates non-covalently with the integrin ß or ß1 (CD29) forming the complex VLA-4, which is expressed on peripheral lymphocytes, thymocytes, eosinophils, basophils, mast cells, dendritic cells, and monocytes. VLA-4 plays a critical role in adhesion and migration of cells into tissues by binding to its ligand VCAM-1 (CD106). In T cells, on ligation of MAdCAM-1, α4β7 integrin also provides costimulation of T cell receptor/CD3–mediated signaling.
