MAdCAM-1 is the acronym for Mucosal addressin cellular adhesion molecule-1 MAdCAM-1 is a transmembrane protein, is mainly expressed by intestinal endothelial cells and plays a crucial role in the immigration of T-lymphocytes into tissues in the gastrointestinal tract. MAdCAM-1 has an IgA-like Ig domain and serves as a ligand of L-selectin and an α4β7 integrin, both of which are involved in lymphocyte homing in Peyer's plaques.
The immunosuppressive biological agent vedolizumab, which acts selectively in the gastrointestinal tract, reduces inflammation in the gastrointestinal tract in patients with ulcerative colitis by inhibiting the interaction of α4β7 with MAdCAM-1. This prevents the migration of memory T lymphocytes migrating into the intestine through the vascular endothelium into the parenchymal tissue.