CCL4, also known as Macrophage Inflammatory Protein-1 beta (MIP-1β), is a chemokine involved in the immune response and inflammation. It is primarily produced by activated monocytes, macrophages, and T cells. CCL4 plays a critical role in recruiting immune cells, particularly T cells, monocytes, and dendritic cells, to sites of infection, injury, or inflammation. It binds to the CCR5 receptor, which is present on various immune cells, promoting their migration and activation. CCL4 is involved in both acute and chronic inflammatory conditions, including infections, autoimmune diseases, and cancer. Its ability to influence immune cell trafficking and activation makes it an important mediator in regulating immune responses.