This gene is one of several chemokine genes clustered on the q-arm of chromosome 17. Chemokines form a superfamily of secreted proteins involved in immunoregulatory and inflammatory processes. The superfamily is divided into four subfamilies based on the arrangement of the N-terminal cysteine residues of the mature peptide. This chemokine, a member of the CC subfamily, displays chemotactic activity on resting T lymphocytes and monocytes, lower activity on neutrophils and no activity on activated T lymphocytes. The protein is also a strong suppressor of colony formation by a multipotential hematopoietic progenitor cell line.