C-C Motif Chemokine Ligand 4 (CCL4) is a 7.66 kDa cytokine with 69 amino acid residues. CCL4, also named macrophage inflammatory protein-1β (MIP-1β), is mainly secreted from neutrophils, monocytes, B cells, T cells, fibroblasts, endothelial cells, and epithelial cells. In addition, CCL4 participates in immune responses, including recruitment of immune cells like lymphocytes, monocytes, and leukocytes, response to IL-1 and IFNγ, and production of TNF when CCL4 binds to CCR5.