“This review article gives a timely update of the development and progress in chemokine research and is focused on the highly competitive area of lymphocyte traffic control.”

This review article gives a timely update of the development and progress in chemokine research and is focused on the highly competitive area of lymphocyte traffic control. It emphasizes the paradigm that predicts an intimate relationship between leukocyte migration properties and leukocyte function. In other words, knowledge about the migration and localization properties of a given type of leukocytes allows us to predict its state of differentiation and function in immune processes. These migration properties are defined by adhesion molecules and chemokines, which form the largest class of cytokines. Chemokines act as chemoattractants by binding to chemokine receptors present on leukocytes. The information in this article is useful to chemokine specialists and those who wish to enter this highly competitive field of research.

This review article is focused on one aspect in chemokine research, namely the contribution of chemokines to the control of lymphocyte traffic. In essence, chemokines guide lymphocyte placement and relocation in all aspects of adaptive immunity, including lymphopoiesis, initiation of effector lymphocyte generation in lymph nodes and lymphocyte recruitment to sites of inflammation as well as immune surveillance of peripheral tissues. Traffic of effector/memory T cells is discussed in great detail.

We have a long-standing interest in this area of research, dating back to the earliest chemokines that were discovered in the late 1980s. One of our main contributions was the discovery that not only cells of the innate immune system, such as neutrophils and monocytes, but also T lymphocytes of the adaptive immune system are targeted by chemokines. Current research activities are centered on the mechanisms controlling the steady-state traffic of long-lived memory T lymphocytes through secondary lymphoid and non-lymphoid tissues.