MIP 4 Human, His

Macrophage Inflammatory Protein-4 (MIP-4), also known as CCL18, is a chemokine belonging to the CC chemokine family. It plays a significant role in the immune system by mediating chemotactic activity, particularly attracting naive T cells, CD4+ and CD8+ T cells, and nonactivated lymphocytes . The recombinant form of this protein, tagged with a His-tag, is widely used in research for its ease of purification and detection.

The gene encoding CCL18 is located on chromosome 17q12 and consists of three exons and two introns . Unlike other chemokines, CCL18 includes two pseudo-exons in the first intron, which do not appear in the final peptide . The mature protein is 69 amino acids long, following the cleavage of a 20 amino acid signal peptide .

CCL18 is primarily produced and secreted by cells of the innate immune system, such as macrophages and dendritic cells . It exerts its effects mainly on the adaptive immune system. The protein has strong chemotactic activity, attracting naive T-cells, B-cells, macrophages, monocytes, and dendritic cells, thereby initiating an immune response . It also plays a role in both humoral and cell-mediated immunity responses .

CCL18 is involved in various pathological conditions. It is highly expressed in patients with allergic asthma and other hypersensitivity diseases . Additionally, it serves as a biomarker for M2 macrophages and has been shown to promote tumor cell proliferation and facilitate immune evasion, aiding in the progression of tumor growth . Elevated levels of CCL18 are also associated with fibrotic diseases and IgG4-related disease .

The His-tag, a series of six to ten histidine residues, is commonly fused to recombinant proteins to facilitate their purification and detection . This tag binds strongly to metal ions such as nickel, cobalt, and copper, allowing for easy isolation of the tagged protein using immobilized metal affinity chromatography (IMAC) . The small size of the His-tag makes it less likely to obstruct the target protein’s structure or function, making it suitable for use under denaturing conditions .