The M5E2 antibody reacts with CD14, an ~53 – 55 kDa GPI-anchored transmembrane glycoprotein expressed at high levels on the surface of peripheral blood monocytes and macrophages, and at lower levels on granulocytes. An ~10-fold difference in expression levels between monocytes/macrophages and granulocytes makes CD14 a useful marker for distinguishing these cell populations. CD14 is also found on tissue macrophages, Langerhans cells and dendritic cells. CD14 functions as a high-affinity receptor for complexes of lipopolysaccharide (LPS) and serum LPS-binding protein and modulates LPS-dependent signal transduction during the immune response to gram-negative pathogens by acting as a co-receptor for TLR 4 and MD-2. This triggers activation of NF-kappa-B, cytokine secretion, and induction of the inflammatory response. Two soluble forms of CD14 have also been described (~48 and ~55 kDa).

This antibody clone has been verified for purity assessments of cells isolated with EasySep™ kits, including EasySep™ Human Myeloid Positive Selection Kit (Catalog #18653) and EasySep™ Human CD14 Positive Selection Kit (Catalog #18058); partial blocking may be observed, as well as EasySep™ HLA Whole Blood CD33 Positive Selection Kit (Catalog #18287HLA), EasySep™ HLA Whole Blood Myeloid Positive Selection Kit , and EasySep™ Human Buffy Coat CD14 Positive Selection Kit.