Macrophage Inflammatory Proteins (MIP) belong to the family of chemotactic cytokines known as chemokines. In humans, there are two major forms, MIP-1α and MIP-1β that are now officially named CCL3 and CCL4, respectively. CCL4, also known as Macrophage inflammatory protein-1β (MIP-1β) is a CC chemokine with specificity for CCR5 receptors. It is a chemoattractant for natural killer cells, monocytes and a variety of other immune cells. CCL4 is a major HIV-suppressive factor produced by CD8 T cells.Perforin-low memory CD8 T cells that normally synthesize CCL4. The cDNAs for human CCL4 encode precursor proteins with a 23 amino acid residue signal peptide that is cleaved to generate the 69 amino acid residue, non-glycosylated mature protein. CCL4 was reported to be twenty-fold less active than CCL3 on the same cell populations. Chemokine activities are mediated by G-protein-coupled seven transmembrane domain receptors . The β chemokine receptor designated CC chemokine receptor-1 (CC CKR-1), alternately named CCL3/RANTES receptor, has been shown to bind CCL3, RANTES, CCL4 and MCP-1 with varying affinities .