CD14 (also known lipopolysaccharide (LPS) receptor) is expressed strongly on monocytes and macrophage and weakly on the surface of neutrophils. CD14 is anchored to cells by linkage to glycosylphosphatidylinositol (GPI) and functions as a high affinity receptor for complexes of LPS and LPS binding protein (LBP). Soluble CD14, also binding to LPS, acts at physiological concentration as an LPS agonist and has, at higher concentrations, an LPS antagonizing effect in cell activation. CD14 has been shown to bind apoptotic cells.
The CD14 is produced from human CD14 transfected CHO-cells. Before transfection the complete human CD14-cDNA was amplified by PCR and cloned into expression vector p-POL-DHFR. 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 containing 335 amino acids.