Structural studies of superantigens: Crystal structure of Streptococcus dysgalactiae-derived mitogen (SDM)

Superantigens are a family of bacterial and viral toxins that are able to induce a massive T-cell activation [1,2]. Compared to conventional antigens where only 0.0001-0.01% of T-cells are activated, superantigens are able to activate 10-30% of T-cells. Superantigen-induced T-cell activation results in an extensive production of inflammatory cytokines, such as tumor necrosis factor and interleukin-2. Consequently, superantigens are responsible for acute diseases, including toxic shock syndrome and food poisoning. In addition, there are reports that superantigens may also be implicated in autoimmune diseases.