CD300LG, also known as nepmucin (a not expressed in Peyer's patches mucin), is a member of the CD300 antigen like family. It is a 50-95 kD glycoprotein with one IgV like domain and one mucin like domain and four isoforms are produced by alternative splicing. Nepmucin is expressed on high endothelial venules (HEV) from lymph nodes, but is absent on HEV from the Peyer's patches. CD300LG mediates lymphocyte adhesion through the intraction of its Ig domain with ICAM-1 and rolling on HEVs through the interaction of its mucin like domain with L-selectine. Also, it may play a role in the molecular transcytosis across the capillary endothelium.