Recombinant Human CCL15/MIP-1 delta/LKN-1 (68 aa) Protein

CCL15, also named Leukotactin-1 (LKN-1), MIP-5, HCC-2, and NCC-3, is a novel human CC chemokine whose gene was mapped to human chromosome 17 adjacent to the HCC-1 gene. CCL15/LKN-1, together with mouse C10, mouse MIP-1 gamma and human MPIF-1, constitute a subgroup of CC chemokines which contain six instead of four conserved cysteine residues. The two additional cysteine residues in CCL15/LKN-1 have been shown to form a third disulfide bond CCL15/LKN-1 cDNA encodes a 113 amino acid (aa) residue precursor protein with a putative signal peptide of 21 aa residues that is cleaved to generate a 92 aa residue mature protein. In recombinant CCL15/LKN-1 preparations produced in insect cells and in yeast, amino-terminal truncations were found to have occurred. The major forms of CCL15/LKN-1 secreted by insect cells and yeast were reported to be proteins of 68 and 66 aa residues, respectively. The full length and the amino-terminal truncated forms of human CCL15 delta/LKN-1 have been shown to be potent chemoattractants for monocytes and T-lymphocytes. These proteins can also chemoattract eosinophils and have been shown to induce calcium flux in human CCR1 transfected cells. Additionally, CCL15/LKN-1 can suppress colony formation by human granulocyte-macrophage, erythroid, and multipotential progenitor cells stimulated by combinations of growth factors. As a chemoattractant for THP-1 cells, R&D Systems’ 68 aa residue truncated form of CCL15 is approximately 50-fold more active than the 92 aa residue full length CCL15/LKN-1.