Eotaxin-3, also named CCL26 or SCYA26, is a novel human CC chemokine that maps to chromosome 7q11.2, within 40 kilobases of the Eotaxin-2 loci. Eotaxin-3/CCL26 has been shown to be constitutively expressed in the heart and ovary. In addition, low levels of Eotaxin-3/CCL26 expression can also be detected in various tissues. The expression of Eotaxin-3/CCL26 in vascular endothelial cells has been shown to be up-regulated by IL-13 and IL-4.
Eotaxin-3/CCL26 cDNA encodes a 94 amino acid (aa) residue protein with a putative signal peptide of either 23 or 26 aa residues. Recombinant Eotaxin-3/CCL26 has been produced in insect cells using a baculovirus expression system and shown to contain 71 aa residues. Recombinant Eotaxin-3/CCL26 is chemotactic for eosinophils and PHA-activated T cells. Eotaxin-3/CCL26 induces calcium flux in eosinophils as well as in CCR3-transfected cells. Eotaxin-3/CCL26 has also been shown to cross-desensitize cells to other CCR3 ligands. Both the 71 aa residue and 68 aa residue variants of recombinant Eotaxin-3 have been expressed in E. coli and found to have equal potency in inducing chemotaxis of a human CCR3-transfected cell line.
