Migration of naive and effector T lymphocytes

Naive T lymphocytes home to lymph nodes as a result of L-selectin binding to its ligan on High Endothelial Venules (HEVs), which are present only in lymph nodes, and as a result of binding chemokines (CCL19 and CCL21) displayed on the surface of the HEV.  Activated T lymphocytes, including effector cells, home to sites of infection in peripheral tissues, and this migration is mediated by E- and P-selectins and integrins, and chemokines that are produced at sites of infection.  Additional chemokines and chemokine receptors, besides the ones shown, are involved in effector/memory T cell migration.