A key role for CCR7 in establishing central and peripheral tolerance

Early studies identified the CC-chemokine receptor (CCR)7 as an important homing molecule controlling the lymph node entry of naive T cells through high endothelial venules and of activated mature dendritic cells through afferent lymphatics. Consequently, these properties initially branded CCR7 as a central organizer of the primary immune response. However, recent studies have demonstrated that a variety of immune cells crucially rely on CCR7-directed migration not only for the induction of protective immunity but also for the establishment of immunological tolerance. In this review, we therefore highlight some of the recent advances in understanding the multiple roles of CCR7 in the induction and maintenance of central and peripheral tolerance.