CD83 (Cluster of Differentiation 83) is a human protein encoded by the CD83 gene. The membrane-bound form of CD83 consists of an extracellular V-type immunoglobulin-like domain, a transmembrane domain and a cytoplasmic signaling tail. A free soluble form consists of the immunoglobulin-like domain alone. Membrane-bound CD83 is expected to form trimers. Soluble CD83 is able to assemble into dodecameric complexes. The CD83 gene is located on human chromosome 6p23 and mouse chromosome 13. In humans, a promoter 261 bp upstream consists of five NF-κB and three interferon regulatory factor binding sites, reflecting the involvement of CD83 in inflammation, as well as binding sites for the aryl hydrocarbon receptor. The latter also occur in an enhancer sequence located 185 bp downstream, inside the second intron, and may suggest negative regulation of transcription by microbial metabolites produced in the gut.