Regulation of leukocyte transmigration: cell surface interactions and signaling events.

Regulation of Leukocyte Transmigration: Cell Surface Interactions and Signaling Events Yuan Liu,* Sunil K. Shaw, Shuo Ma, Lin Yang, Francis W. Luscinskas, and Charles A. Parkos* A fundamental event in the inflammatory response is recruitment of blood leukocytes to a site of injury or infection, often resulting in tissue dysfunction and damage. The steps in this recruitment process are leukocyte adhesion to the endothelial lining of the vessel wall, diapedesis, or transmigration across the endothelial monolayer, followed by directed migration to a site of infection or injury that often involves transmigration across epithelia. This review will highlight recent advances in our understanding of the mechanisms of leukocyte-endothelial and leukocyte-epithelial cell adhesive interactions at the level of cell surface protein-protein binding events, and in intracellular signal transduction pathways that regulate leukocyte egress out of the vascular space and into epithelial-lined tissues.