CD209, known as Dendritic Cell-Specific Intercellular adhesion molecule 3 (ICAM-3)-Grabbing Nonintegrin (DC-SIGN), is a 44 kD type II transmembrane glycoprotein and a member of the C-type lectin family. CD209 is expressed on myeloid dendritic cells, placental macrophages, liver and placental endothelial cells. CD209 binds to ICAM-3 (CD50), ICAM-2 (CD102), and Butyrophilin (BTN2A1), and mediates dendritic cell migration and T cell proliferation. Importantly, CD209 is a receptor of HIV-1 and some other viruses (such as West Nile virus, hepatitis C virus, etc), and some bacteria or parasites. It plays a critical role in capturing and internalizing those pathogens. LSP1 (leukocyte-specific protein 1) interacts with the cytoplasmic domain of CD209 and mediates transport of HIV to the proteasome.