The lymphocyte Peyer's patch adhesion molecule (LPAM-1), also known as integrin a4ß7, is a member of the integrin family of cell surface receptors. It is expressed primarily on mucosal lymphocytes but is also present on NK cells and eosinophils. The a4ß7 heterodimer mediates the binding of lymphocytes to its ligand, mucosal vascular addressin (MAdCAM-1) on the high endothelial venules, thereby directing the homing of lymphocytes into Peyer's patches and intestinal lamina propria. The monoclonal antibody DATK32 recognizes a conformational epitope on the heterodimer.