T cell activation by the exotoxins having superantigenic properties and abonormal reactions observed in patients with the toxin-associated illness.

大多数细菌超抗原（SAg），如中毒性休克综合征毒素-1 （TSST-1）、葡萄球菌肠毒素（SE）和链球菌热原外毒素（SPE），都与某些表现出急性和全身临床症状的传染病的发病机制有关。我们认为细菌SAg对T细胞的激活主要参与了这些细菌引起的感染性疾病的发病机制。我们证明，在表达MHC II类分子的辅助细胞（AC）存在的情况下，这些毒素以T细胞受体v β选择性的方式激活大量T细胞。本课题的研究成果如下：1。MHC II类分子在AC上的表达是sag诱导的人T细胞产生tnf - α和tnf - β所必需的。在sag诱导的tnf - α和tnf - β生成方面，T细胞远高于CD8^+ T细胞，也远高于CD8^+ T细胞。ifn -g刺激的人血管内皮细胞作为AC在sag诱导的人T细胞中产生tnf - α和tnf - β。我们纯化并鉴定了一种新的假结核耶尔森菌产生的有丝分裂物质（YPM），该物质是从表现急性和全身症状的患者中分离出来的。YPM是一种有效的T细胞激活剂，具有超抗原特性。

Most of bacterial superantigens (SAg), such as toxic shock syndrome toxin-1 (TSST-1), staphylococcal enterotoxins (SE), and streptococcal pyrogenic exotoxins (SPE), are implicated in pathogenesis of certain infectious diseases manifesting acute and systemic clinical symptoms. We have considered that T cell activation by bacterial SAg is primarily involved in the pathogenesis of the infectious diseases caused by these bacteria. We demonstrated that these toxins activate a large number of T cells in a T-cell receptor Vbeta selective way in the presence of accessory cells (AC) expressing MHC class II molecules. The results in this project are as follows :1. The expression of MHC class II molecules on AC is required for SAg-induced TNF-alpha and TNF-beta production in human T cells.2.T cells is much higher than that of CD8^+ T cells is much higher thant that of CD8^+ T cells in SAg-induced TNF-alpha and TNF-beta production.3. IFN-g-stimulated human vascular endothelial cells function as AC for SAg-induced TNF-alpha and TNF-beta production in human T cells.4. We purified and characterized a novel mitogenic substance (YPM) produced by Yersinia pseudotuberculosis isolated from patients manifesting acute and systemic symptoms.5. YPM is a potent T cell activator and has superantigenic properites.