Recombinant Human CD300g/Nepmucin Fc Chimera Protein, CF

Nepmucin, also known as CMRF35-like molecule 9 (CLM-9), TREM-4 and CD300g, is a 75-95 kDa type I transmembrane O-glycosylated member of the CD300 family of molecules. Nepmucin (mucin not expressed in Peyer's Patches) is expressed on capillary endothelium and its expression appears to be influenced by factors that are locally produced in tissues (1, 2). Nepmucin contains a single V-type immunoglobulin domain and a mucin-like domain (3). Mature human nepmucin is composed of 314 amino acid (aa), containing 229 aa extracellular domain (ECD), a 21 aa transmembrane segment, and a 64 aa cytoplasmic region. Within the ECD, human nepmucin shares 53% aa identity with mouse nepmucin. Nepmucin plays a critical role in promoting lymphocyte transendothelial migration of high endothelial veins and mediates lymphocyte adhesion with endothelial cells by its Ig domain, which is independent of LFA-1 or VLA-4 adhesion pathway (3). Glycosylated nepmucin with MECA-79 epitope associate with L-selectin to mediate L-selectin-dependent lymphocyte rolling by its mucin-like domain (4). Expression of nepmucin is down-regulated in tumours and tumour-draining lymph nodes, indicating that the expression of nepmucin is negatively regulated by locally produced signals under these circumstances (2). Nepmucin induction can significantly improve the killing activity of CIK cells (5).