Superantigens bind to major histocomi>atibility complex (Ml 1C) class II molecules on antigen presenting cells (Al'(') and stimulate a large proftortion of T cells bearing appropriate T cell receptors l ’p (TCR-l ’¡¡) gene segments. Su/>erantigens are produced bv bacteria, mycoplasmas. retroviruses, and probably by parasites. Sti/teranligens are distinguished j'rom conventional antigens by their caftacity to induce selective expansion of large numbers of T cells expressing particular I ^ gene segments and to be presented in a MIIC-dependent but MIIC non-restrictcd manner. Su/>erantigens have multi/tie pleiotropic ejfects in vivo, causing the activation, proliferation, anergv and deletion of specific T cells. This review gives an oven’iew of microbial siil>erantigens and summarizes current thinking about their interactions with T cells and their jmssible significance in pathogenesis. [Journal ofTurgut Oza! Medical C'enter I(3):219-229,1994]
Key Words'. Superantigen. APC, TCR. enterotoxin, exotoxin
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