Roles of Chemokines in Immune Cell Trafficking to Lymphoid Tissues

Abstract

Immunological protection requires the appropriate distribution and cellular interaction of innate and acquired immune cells within the body. Most immune cell populations undergo a hierarchal process of development, beginning as hematopoietic stem cells in the bone marrow. Mature and some immature immune cells then traffic between the lymphoid and nonlymphoid tissues via the blood and lymph circulation. Accumulating evidence has helped to unravel the roles of the chemokine system in the spatiotemporal regulation of immune cell trafficking to, localization and cellular interaction within, and egress from the lymphoid tissues. In the primary lymphoid tissues, chemokines play a pivotal role in the retention of immature immune cells until they mature, and then regulate the egress and homing of mature immune cells. In the secondary lymphoid tissues, chemokines promote immune cell entry and the intratissue compartmentalization that is required for efficient interaction between lymphocytes and antigen-presenting cells. This section explains the current understanding of the role of chemokines in immune cell trafficking to, localization within, and egress from the lymphoid tissues in mice.