CCR7 Ligands, SLC/6Ckine/Exodus2/TCA4 and CKβ-11/MIP-3β/ELC, Are Chemoattractants for CD56+CD16−NK Cells and Late Stage Lymphoid Progenitors

Two human CC chemokines, SLC/6Ckine/Exodus2/TCA4 and CKβ-11/MIP-3β/ELC, are previously reported as efficacious chemoattractants for T- and B-cells and dendritic cells. SLC and CKβ-11 share only 32% amino acid identity, but are ligands for the same chemokine receptor, CCR7. In this study, we examined chemotactic activity of SLC and CKβ-11 for NK cells and lymphoid progenitors in bone marrow and thymus. It was found that these two CCR7 ligands are chemoattractants for neonatal cord blood and adult peripheral blood NK cells and cell lines. SLC and CKβ-11 preferentially attract the CD56+CD16−NK cell subset over CD56+CD16+NK cells. SLC and CKβ-11 also demonstrate selective chemotactic activity on late stage CD34−CD19+IgM−B-cell progenitors and CD4+and CD8+single-positive thymocytes, but not early stage progenitors. It was noted that SLC is an efficient desensitizer of CKβ-11-dependent NK cell chemotaxis, while CKβ-11 is a weak desensitizer of SLC-dependent chemotaxis. Taken together, these results suggest that SLC and CKβ-11 have the potential to control trafficking of NK cell subsets and late stage lymphoid progenitors in bone marrow and thymus.