SLC (secondary lymphoid tissue chemokine), also known as 6Ckinc and Exodus-2, is one of the homeostatic che-mokines that are constitutively expressed in various lymphoid tissues and attracts mainly lymphocytes, but not monocytes or granulocytes. SLC plays a major role in the homing of naive T cells and antigen-bearing dendritic cells to the T cell areas of secondary lymphoid tissues, and thus promotes the encounter of these cell types to initiate the immune responses. SLC signals through CCR7. Although SLC and ELC share only 32% amino acid identity, ELC/MIP-beta also binds CCR7. In addition, their genes are closely linked on human chromosome 9pl3, a locus separated from the main CC chemokine gene cluster on chromosome 17. Recently, mice with the paucity of lymph node T cell (pit) mutation, which have a failure in homing of both naive T cells and dendritic cells to secondary lymphoid tissues, were found to have a defect in the expression of SLC.