Biological activity of cytolysins produced by Gram-positive bacteria and their involvement in the response of infected

革兰氏阳性菌产生的溶细胞素的生物活性及其与感染反应的关系

基本信息

批准号：
12470063
负责人：
MITSUYAMA Masao
金额：
$ 8.7万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Various species of Gram-positive bacteria produce cholesterol-dependent cytolysins(CDCs). We have constructed several. CDC proteins including amino- acid replacement and truncation, in-order to analyze the molecular mechanism of cytolysis and cytokine induction. CDC family proteins LLO, LSO and PLY produced by L. monocytogenes, L. seeligeri, and S. pneumoniae, respectively showed domain 4-deperident cytolytic activity and cytokine-inducing activity that was not dependent on domain 4 as well. It was found that the different domains of the same protein molecule are responsible for different biological activities. LLO induced IL-12 and IL-18 production from macrophages, and in turn these cytokines induced NK-cell dependent IFN-g. TLR2/TLR4/CD14 appeared to be involved in the cytokine response of macrophages, and domain 1-3 was capable of inducing NF-kB activation. Though most of the recombinant CDC proteins exhibited the cytokine-inducing ability, ILO derived from L. ivanovii was not active in cytokine induction despite of the high homology to LLO and LSO. It appeared that N-terminal sequence of domain 1 was highly essential for the cytokine-inducing activity, we have constructed various amino acid replacement. It was found that the PEST sequence is important in the activity. This study clearly indicated that many CDC family proteins of Gram-positive bacteria are active in cytokine-induction that is different from a well-known cytolytic activity. This novel activity appeared to be involved in the host response in the infection by CDC-producing Gram-positive bacteria.

多种革兰氏阳性菌产生胆固醇依赖性溶细胞素（CDC）。我们已经建造了几个。 CDC蛋白包括氨基酸替换和截短，以分析细胞溶解和细胞因子诱导的分子机制。由单增李斯特菌、西利氏李斯特菌和肺炎链球菌产生的 CDC 家族蛋白 LLO、LSO 和 PLY 分别表现出依赖于结构域 4 的溶细胞活性和不依赖于结构域 4 的细胞因子诱导活性。研究发现，同一蛋白质分子的不同结构域负责不同的生物活性。 LLO 诱导巨噬细胞产生 IL-12 和 IL-18，进而这些细胞因子诱导 NK 细胞依赖性 IFN-g。 TLR2/TLR4/CD14 似乎参与巨噬细胞的细胞因子反应，并且结构域 1-3 能够诱导 NF-kB 激活。尽管大多数重组CDC蛋白表现出细胞因子诱导能力，但源自L.ivanovii的ILO尽管与LLO和LSO具有高度同源性，但在细胞因子诱导中并不活跃。看来结构域 1 的 N 端序列对于细胞因子诱导活性非常重要，我们构建了各种氨基酸替换。结果发现PEST序列在该活动中很重要。这项研究清楚地表明，革兰氏阳性菌的许多 CDC 家族蛋白在细胞因子诱导中具有活性，这与众所周知的细胞溶解活性不同。这种新活性似乎与产生 CDC 的革兰氏阳性菌感染时的宿主反应有关。