naive t-lymphocytes leave the bloodstream across the specialized endothelial walls of blood vessels called high endothelial venules or HEV in the t-cell areas of lymphoid organs this specialized endothelium expresses a number of molecules involved in lymphocyte homing to the lymph node in particular the homing receptor glidecam one the adhesion molecule icam one and chemokines such as MIT 3 beta the initial binding of the naive t-cell to the vascular endothelium is mediated by el select and binding to glidecam one subsequently binding of chemokines displayed on the extracellular matrix triggers tight adhesion of the integrand LFA 1 to its ligand I cam 1 the lymphocyte is then able to migrate across the endothelium and into the t-cell area of the lymph node the naive t-cell can now inspect dendritic cells in the lymph node for the presence of its specific antigen if it does not recognize antigen the t-cell is not activated and passes out of the lymph node to return to the circulation t-cells that do meet their specific antigen in the lymph node are activated and begin to proliferate and to mature into effector cells eventually after a few days these cells leave the lymph node and return to the circulation you