ELC (EBIl-ligand chemokine) (Yoshida et al, 1997). also known as MIP-3;'i (macrophage inflammatory protein 3beta and Exodus-3, belongs to a novel class of CC chemokines that is highly expressed in lymphoid tissues and has chemotactic activity for lymphocytes, but not for monocytes or granulocytes. ELC specifically binds and signals through CCR7/EBI1/BLR2. The human gene for ELC (SCYAI9) is located on chromosome 9pl3. which is unusual in that most other CC chemokine genes are mapped on chromosome 17. Another CC chemokine SLC 6Ckine shares the receptor CCR7 with ELC and has its gene on the same chromosome as ELC. although they share only 32% amino acid identity.These findings suggest that ELC and SLC were derived from a common ancestor and have a role in lymphocyte homing into and trafficking within lymphoid tissues and the thymus.