 It also plays an important role in trafficking of T cells in thymus, and in T cell and B cell migration to secondary lymphoid organs.It specifically binds to chemokine receptor CCR7.Chemokine (C-C motif) ligand 19 (CCL19) is a small cytokine belonging to the CC chemokine family that is also known as "EBI1 ligand chemokine" (ELC) and "macrophage inflammatory protein-3-beta" (MIP-3-beta).