Strongly chemotactic for naive (L-selectinhi) CD4 T-cells and for CD8 T-cells and weakly attractive for resting B-cells and memory (L-selectinlo) CD4 T-cells. May play a role in promoting encounters between recirculating T-cells and dendritic cells and in the migration of activated B-cells into the T-zone of secondary lymphoid tissues. Binds to chemokine receptor CCR7. Binds to atypical chemokine receptor ACKR4 and mediates the recruitment of beta-arrestin (ARRB1/2) to ACKR4. Interacts with TNFAIP6 (via Link domain). Highly expressed by dendritic cells in mesenteric and peripheral lymph nodes. Significant expression in spleen (T cell zone or periarteriolar lymphatic sheath) and Peyer patches. Low expression in thymus. Belongs to the intercrine beta (chemokine CC) family.