Fleischer B, Mittrücker H W, Metzroth B, Braun M, Hartwig U
I. Department of Medicine, University of Mainz, Germany.
Behring Inst Mitt. 1991 Feb(88):170-6.
The enterotoxins produced by Staphylococcus aureus (SE) are prototypes of a group of microbial exoproteins that share a potent mitogenic activity for T lymphocytes of several species. These exoproteins use a very effective novel mechanism of T lymphocyte stimulation. For stimulation of all types of T cells (CD4+, CD8+ as well as gamma delta TCR+) the presence of allogeneic or xenogeneic MHC class II molecules on accessory or target cells is required. This requirement is reflected by a selective binding of the toxins to MHC class II molecules. The toxins stimulate preferentially but not exclusively alpha beta TCR+ T cells carrying certain TCR V beta s. A current model suggests that the toxins are functionally bivalent molecules, crosslinking variable parts of the TCR with MHC class II molecules on the accessory or target cells. Of all T cell mitogens the toxins thus most closely simulate T cell recognition of specific antigen. The differential pattern of reactivity of human and murine T cells with various toxins suggests that the toxins have been adapted to the host's immune system in evolution.
金黄色葡萄球菌（SE）产生的肠毒素是一类微生物外毒素的原型，这类外毒素对多种物种的T淋巴细胞具有强大的促有丝分裂活性。这些外毒素采用了一种非常有效的新型T淋巴细胞刺激机制。为了刺激所有类型的T细胞（CD4+、CD8+以及γδTCR+），辅助细胞或靶细胞上需要存在同种异体或异种MHC II类分子。毒素与MHC II类分子的选择性结合反映了这一需求。毒素优先但并非唯一地刺激携带某些TCR Vβs的αβTCR+ T细胞。目前的模型表明，毒素是功能上的二价分子，将TCR的可变部分与辅助细胞或靶细胞上的MHC II类分子交联。因此，在所有T细胞促有丝分裂原中，毒素最接近模拟T细胞对特定抗原的识别。人类和小鼠T细胞对各种毒素的不同反应模式表明，这些毒素在进化过程中已适应宿主的免疫系统。
