CD14 is a 55 kDa GPI-anchored glycoprotein that is constitutively expressed on the surface of mature monocytes, macrophages, and neutrophils. CD14 also serves as a multifunctional lipopolysaccharide receptor, and is released to the serum both as a secreted and enzymatically cleaved GPI-anchored form. CD14 binds lipopolysaccharide molecule in a reaction catalyzed by lipopolysaccharide-binding protein (LBP), an acute phase serum protein. The soluble sCD14 can discriminate slight structural differences between lipopolysaccharides and is important for neutralization of serum allochthonous lipopolysaccharides by reconstituted lipoprotein particles. Further, CD14 has been shown to bind apoptotic cells, and can affect allergic, inflammatory and infectious processes. Alternative splicing results in multiple transcript variants encoding the same CD14 isoform. Diseases associated with CD14 dysfunction include mycobacterium chelonae infection and Croup.
monocyte differentiation antigen CD14; myeloid cell-specific leucine-rich glycoprotein