ゲノムバイオロジーを基盤とする黄色ブドウ球菌の分子疫学と危害評価

近年来，许多新的葡萄球菌肠毒素（SE）被报道。已知某些SE基因与移动的遗传元件如致病岛、原噬菌体和质粒相关。这些事实表明，超抗原毒素基因在葡萄球菌菌株之间水平转移。这些移动的遗传元件可能在金黄色葡萄球菌作为病原体的进化中发挥了重要作用。为了研究这些新发现的金黄色葡萄球菌的病理生物学和流行病学，我们进行了以下研究：1.我们利用四套多重PCR技术建立了18种经典和新描述的金黄色葡萄球菌超抗原毒素基因的综合检测体系。对69株食物中毒金黄色葡萄球菌和97株健康人鼻拭子分离株进行超抗原毒素基因分型，共发现32种超抗原毒素基因型，表明许多金黄色葡萄球菌具有多种毒素基因。Ana ...更多信息 毒素基因型和编码移动的遗传元件谱的毒素基因之间的关系的裂解表明其在确定金黄色葡萄球菌中作为毒素基因编码移动的遗传元件的组合的超抗原毒素基因型中的可能作用（FEMS微生物学通讯，246：191- 198，2005）。2.利用转座组学方法测定了sed、selj和selj编码质粒p196的全核苷酸序列。该质粒编码青霉素抗性操纵子和镉抗性操纵子，以及三种SE（SE 1）基因。3.我们鉴定了一种新的葡萄球菌肠毒素（SE）样推定毒素SE 1 R。SE 1 R蛋白显示出显著的T细胞刺激活性。SER刺激携带Vβ 3、11、12、13.2和14受体的T细胞。以上结果表明SER是一种超抗原（Infection and Immunity 72：3664，2004）。4.研究了一种新的葡萄球菌肠毒素（SE）样毒素P型（SE 1 P）的生物学特性。当以0.4 pM或更高的浓度给药时，SE 1 P诱导了大量的增殖反应和人T细胞产生细胞因子IL-2、IFN-γ、TNF-α和IL-4。辅助细胞上MHC II类分子的表达是SE 1 P刺激T细胞所必需的。SE 1 P选择性刺激大量携带Vβ 5.1、6、8、16、18和21.3受体的人T细胞。这些结果表明，SE 1 P作为超抗原。SE 1 P在家麝鼩呕吐试验中被证明是呕吐的，尽管在相对高的剂量下（Infection and Immunity，73：in press，2005）。5.我们构建并表达了无毒突变体SEC（mSEC），并研究了用没有超抗原活性的mSEC免疫是否可以保护免受金黄色葡萄球菌感染。用mSEC免疫小鼠并用活的金黄色葡萄球菌攻击。mSEC免疫组小鼠脏器细菌计数显著低于对照组，存活率显著高于对照组。用mSEC免疫强烈诱导T辅助细胞2型抗体、免疫球蛋白G1和免疫球蛋白G2 b的产生。用缺乏超抗原特性的mSEC免疫提供了针对金黄色葡萄球菌感染的保护，并且该保护可能由IL-10和IL-4诱导和IFN-γ的下调以及SEC中和抗体介导（Infection and Immunity，73：174- 180，2005）。少

In recent years, many new staphylococcal enterotoxins (SEs) have been reported. It has been known that certain SE genes are associated with mobile genetic elements such as pathogenicity islands, prophages, and plasmids. These facts imply that superantigenic toxin genes are transferred horizontally between staphylococcal strains. There is a possibility that these mobile genetic elements have played an important role in the evolution of S.aureus as a pathogen. To investigate pathobiology and epidemiology of these newly identified SEs, we had undertaken studies shown in below.1.We have developed a comprehensive detection system for 18 kinds of classical and newly described staphylococcal superantigenic toxin genes using four sets of multiplex PCR. Superantigenic toxin genotyping of Staphylococcus aureus for 69 food poisoning isolates and 97 healthy human nasal swab isolates revealed 32 superantigenic toxin genotypes and showed that many S.aureus isolates harbored multiple toxin genes. Ana … More lysis of the relationship between toxin genotypes and toxin genes encoding profiles of mobile genetic elements suggests its possible role in determining superantigenic toxin genotypes in S.aureus as combinations of toxin gene-encoding mobile genetic elements (FEMS Microbiology Letters,246 : 191-198,2005).2.We have determined complete nucleotides sequence of sed, selj and selj encoding plasmid, p196, using transposomics strategy. This plasmid is encoding penicillin resistance operon and Cd-resistance operon, in addition to three kinds of SE (SE1) genes.3.We characterized a novel staphylococcal entertoxin (SE)-like putative toxin SE1R. The SE1R protein showed significant T cell stimulation activity. MHC class II molecules were required for T cell stimulation by SER. SER stimulated T cells bearing receptors Vβ3,11,12,13.2, and 14. These results suggested that SER acts as a superantigen (Infection and Immunity 72 : 3664,2004).4.We investigated the biological properties of a novel staphylococcal enterotoxin (SE)-like toxin type P (SE1P). SE1P induced a substantial proliferative response and the production of cytokines IL-2, IFN-γ, TNF-α, and IL-4 from human T cells when administered at a concentration of 0.4 pM or more. The expression of MHC class II molecules on accessory cells was required for T cell stimulation by SE1P. SE1P selectively stimulated a vast number of human T cells bearing receptors Vβ 5.1,6,8,16,18, and 21.3. These results indicated that SE1P acts as a superantigen. SE1P proved to be emetic in the house musk shrew emetic assay, although at a relatively high dose (Infection and Immunity, 73 : in press,2005).5.We constructed and expressed a non-toxic mutant SEC (mSEC) and investigated whether immunization with mSEC, devoid of superantigenic activity, can protect against S.aureus infection. Mice were immunized with mSEC and challenged with viable S.aureus. Bacteria counts in the organs in mSEC-immunized mice were significantly lower and the survival rate was higher than those of the control group. Immunization with mSEC induced strongly the production of T-helper 2 type antibodies, immunoglobulin G1 and immunoglobulin G2b. Immunization with mSEC devoid of superantigenic properties provides protection against S.aureus infection and the protection might be mediated by the IL-10 and IL-4 induction and down-regulation of IFN-γ, as well as SEC neutralizing antibodies (Infection and Immunity, 73 : 174-180,2005). Less