The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates that encodes MHC molecules. MHC molecules play an important role in the immune system and autoimmunity. Proteins are continually synthesized and destroyed in the cell. These include normal proteins (self) and microbial pathogens (nonself). The MHC proteins act as "signposts" that serve to alert the immune system if foreign material is present inside a cell. They achieve this by displaying fragmented pieces or antigens on the host cell's surface...