Integrins are transmembrane receptors that, upon activation by chemokines, facilitate firm adhesion of leukocytes to the endothelium. They bind to counter-receptors such as ICAM-1 and VCAM-1 on endothelial cells. The high-affinity binding of integrins to these molecules is crucial for the subsequent transmigration of leukocytes across the endothelial barrier.
