CD14 acts as a receptor for endotoxin (LPS), is expressed strongly on monocytes and macrophages and weakly at the cell surface of neutrophils. CD14 is anchored to cells by linkage to glycosylphosphatidylinositol (GPI) and functions as a high affinity receptor LPS-LBP (lipopolysaccharide binding protein) complex. Furthermore CD14 is present in a soluble form in human serum, urine and other body fluids, acts at physiological concentrations as an LPS agonist, and, at higher concentrations, has an antagonizing effect in cell activation. The myeloid differentiation antigen CD14 acts as the major receptor for bacterial LPS. The dominant form of the recombinant wild type CD14 is the 50 kDa protein.
Recombinant Mouse CD14 is produced from mouse CD14 transfected CHO-cells in serum free medium and purified by TALON His-tag purification. Before transfection, the complete mouse CD14-cDNA was amplified by PCR and cloned into expression vector p-POL-DHFR. A DNA sequence encoding the extracellular domain (Met1-Pro345) of mouse CD14 precursor was fused with a polyhistidine tag sequence at the C-terminus.