ABSTRACT
This chapter discusses recent highlights of the role of integrins in T-cell trafficking and T-cell responses, with a particular emphasis on the signaling functions of integrins. A distinguishing characteristic of leukocytes is their motility, a necessary feature for immune surveillance as well as migration to sites of tissue injury and inflammation. Lymphocyte trafficking, whether into lymphoid organs during the normal course of recirculation or into tissue during an immune response, involves a cascade of adhesion events during which leukocytes leave blood vessels and extravasate through the vascular endothelial lining into the underlying tissue. The Extracellular Matrix is a complex and highly organized mixture of fibrous proteins, such as collagens, laminin, fibronectin, and proteoglycans. The multistep adhesion cascade model predicts that successful movement of leukocytes from the bloodstream into tissue sites requires a signaling event that rapidly and transiently up-regulates the functional activity of integrin receptors.
