Recombinant Human CCL23/Ck beta 8-1 (aa 46-137) Protein

CCL23 (SCY A23), a splice variant of CK beta8 (also known as MPIF-1), is a beta chemokine isolated from the THP-1 cDNA library. CCL23 cDNA encodes a 137 amino acid (aa) residue precursor protein with a putative 21 aa residue signal peptide. Compared to CK beta8-1, CK beta8/MPIF-1 lacks a 17 aa residue stretch (Leu 47 - Gly 63) present in CCL23 and has a unique arginine at residue 46. CK beta8-1/CK beta8 (MPIF-1) and leukotactin/MIP-1 delta form a subgroup of beta chemokines that have 6 conserved cysteine residues and an extended amino-terminus preceding the conserved cysteine pair. CCL23 shares approximately 73% nucleotide sequence identity with leukotactin (MIP-1 delta), and the two genes have been localized to human chromosome 17 within 200 kb of each other. CCL23 mRNA expression has been detected in the pancreas, heart and skeletal muscle. Both CK beta8-1 and CK beta8 (MPIF-1) are potent agonists of CCR1 and have been shown to chemoattract peripheral blood lymphocytes and monocytes. The two chemokines have also been reported to chemoattract neutrophils and to inhibit colony formation by human hematopoietic progenitor cells. Similar to CK beta8 (MPIF-1), the truncated form of CK beta8-1 (aa 46 - 132) produced at R&D Systems has been shown to have greatly enhanced biological activity compared to the full length mature CK beta8-1 (aa 22 - 132).