Transepithelial migration of neutrophils

Neutrophils are a key cell type of nonadaptive immune system and are the fi rst phagocytic cell type that reaches mucosal inflammatory sites. On the la st stage of their journey from the blood stream to a mucosal surface, neutr ophils cross a generally sealed epithelium by migrating along the paracellu lar pathway to the luminal side of the epithelial layer. This last step inv olves a-specific receptor-mediated adhesion event of the neutrophil to the epithelium, followed by a rapid and highly coordinated reversible opening o f the epithelial intercellular junctions that allows the transmigration of the neutrophils. Although we do not yet understand the molecular mechanisms that mediate this transmigration process, years witnessed the discovery of the first neutrophil and epithelial cell surface proteins critically invol ved in transepithelial migration of neutrophils.