CD301, also known as CLEC10A, macrophage galactose/N-acetylgalactosamine (GalNAc) specific lectin (MGL), DCASGPR, and HML, is a 40 kD type II transmembrane glycoprotein, which belongs to the C-type lectin family. Human CD301 consists of a 39 amino acid (aa) cytoplasmic region, a 21 aa transmembrane segment, and a 256 aa extracellular domain (ECD) with one carbohydrate recognition domain (CRD) and a neck region. CD301 is expressed on immature myleloid dendritic cells and alternatively activated (tolerogenic) macrophages. The expression level is upregulated by immunosuppressant dexamethasone. Human CD301 has an exclusive specificity for rare terminal GalNAc structures, which are revealed on the tumor-associated mucin MUC1 and CD45 (RA, RB, and RC but not RO isoforms). This interaction inhibits effector T cell activation and induces their apoptosis. CD301 also binds the GP envelope glycoprotein on Marburg and Ebola viruses and enhances viral entry and infectivity.