The chemokine (C-C motif) ligand 3 (CCL3), also known as macrophage inflammatory protein 1α (MIP-1α), is a cytokine belonging to the CC chemokine family that is involved in the acute inflammatory state in the recruitment and activation of polymorphonuclear leukocytes. The gene for CCL3 is located on human chromosome 17. The cDNAs of CCL3 encode a 92 amino acid (aa) residue precursor protein with a 22 aa residue signal peptide that is cleaved to generate the secreted mature protein. Like other chemokines, CCL3 is a monocyte chemoattractant. In addition, CCL3 has also been reported to have differential chemoattractant and pro-adhesive effects on T-lymphocytes, NK cells, cytotoxic T cells, B cells, basophils and eosinophils.
CCL3 has been identified as a stem cell inhibitor (SCI) that can inhibit the proliferation of hematopoietic progenitor cells both in vitro and in vivo. CCL3, CCL4 and RANTES have been implicated as the major HIV-suppressive factors produced by CD8 T cells.