CD14 is a glycoprotein expressed on the surface of monocytes, macrophages in follicles, and dendritic cell subsets. CD14 forms a receptor complex with MD-2(LY) and TLR4, which specifically responds and transduces signals to lipopolysaccharide (LPS). The CD14/MD-2/TLR4 receptor complex signals through MyD88, TIRAP, and TRAF6, ultimately activating NF-κB.