SUPERANTIGENS - STRUCTURE AND RELEVANCE TO HUMAN-DISEASE

Superantigens are a class of immunostimulatory molecules produced by b acteria and viruses. Their potent immune effects are due to their uniq ue ability to bind to the major histocompatibility complex (MHC) outsi de the antigen-binding cleft and to stimulate T cells in a T-cell rece ptor (TCR) V beta-specific manner, Structural studies have revealed th e binding sites involved in the MHC/superantigen/TCR complex, The bact erial superantigens are responsible for a number of syndromes, Includi ng food poisoning and toxic shock syndrome, but their effects may be n ot only acute but also chronic and complex, Recent evidence suggests t hat superantigens may be relevant to the pathogenesis of autoimmune an d immunodeficiency disorders. To illustrate the detrimental effects of superantigens on disease outcome, evidence demonstrating the modulati on of experimental allergic encephalomyelitis, an animal model for mul tiple sclerosis, by superantigen, as well as the potential role of sup erantigens in HIV pathogenesis of AIDS, will be presented. The informa tion presented may provide valuable insight into the role of superanti gens in autoimmunity and HIV infection.