MIP-1β (macrophage inflammatory protein-1β), or CCL4L1 (C-C motif chemokine ligand 4 like 1), is a CC chemokine gene localized to human chromosome 17q12. It is a copy number variable gene which shares 95% sequence homology with its non-copy number variable paralogues CCL4. MIP-1β is expressed by a wide range of cells including immune cells, such as monocytes, B and T cells, fibroblasts, endothelial, and epithelial cells.
MIP-1β (macrophage inflammatory protein-1β), or CCL4L1 (C-C motif chemokine ligand 4 like 1), interacts with its major G protein-coupled receptors CCR5 and CCR8, and promotes the migration of immune cells, such as monocytes, natural killer (NK) cells, and T cells, maturation of dendritic cells (DCs), T cell and granulocyte activation, and T cell differentiation. It is an age associated inflammatory cytokine, and it shows elevated expression in the monocytes and blood of elderly individuals. MIP-1β plays a wide role in immune responses, and hence, its expression is tightly controlled during T-cell differentiation and activation.
