CD68 belongs to a growing family of hematopoietic mucin-like molecules known as lysosomal/endosomal-associated membrane glycoproteins (LAMPs). Other LAMP family members included leukosialin, stem cell antigen CD34, and GlyCAM-1. CD68 encodes a 110-kD transmembrane glycoprotein with high levels of expression in human monocytes and tissue macrophages. CD68 binds lectins through a heavily glycosylated extracellular domain.