CD83 is a 40-45 kDa heavily glycosylated type I cell surface glycoprotein of immunoglobulin family. It is expressed on the surface of mature dendritic cells, Langerhans cells in the skin, and interdigitating reticulum cells in the lymphoid tissues. Low expression of CD83 has been reported in activated T and B cells. Cytoplasmic expression of CD83 can be detected also in monocytes and macrophages. CD83 is involved in modulation of antigen presentation. Soluble CD83 has immunoregulatory functions, it is able to down-regulate dendritic cell maturation and stimulation of T cells. In the developing immune system, release of soluble CD83 from dendritic cells upon stimulation by gram-positive or gram-negative bacteria has anti-allergic effect. Herpes simplex virus, on the other hand, causes CD83 degradation in mature dendritic cells.
