Langerhans cells (LCs) are a subset of immature dendritic cells (DCs) that specifically localize in the epidermis and other mucosal epithelia. Epidermal LCs possess a strong immuno-stimulatory capacity and play a central role in initiating and regulating immune responses. Langerin (CD207) is a Ca2+-dependent, C-type lectin domain containing type II transmembrane protein that induces epidermal LCs to differentiate into Birbeck granules (BG). BGs are organelles with superimposing and zippering membranes that influence proper class I type antigen presentation to the circulating T cells. The human spleen, lymph node, thymus, liver, lung, and heart express Langerin protein.