Concerted action of the chemokine and lymphotoxin system in secondary lymphoid-organ development.

Chemokines are essential regulators of lymphocyte migration throughout the body. The chemokine system controls lymphocyte recirculation in immune-system homeostasis, as well as the activation-dependent and tissue-selective trafficking of effector and memory lymphocytes during immune responses. In addition, there is now substantial evidence that chemokines are critical factors for the development and organization of secondary lymphoid organs and that they are involved in all stages of lymphoid organogenesis.