Molecular mechanisms required for injection of Yersinia outer proteins (Yops) into host cells, and consequences for the host immune response

许多病原菌表达三型分泌系统（TTSS），通过该系统它们将毒素注入宿主细胞以逃避宿主的防御机制。致病性小肠结肠炎耶尔森氏菌的一个重要毒力机制是通过TTSS将耶尔森氏菌外蛋白（Yops）注入宿主细胞。利用β-内酰胺酶报告基因系统对Yop注射液进行追踪研究，使我们对Yop注射液有了新的认识.小肠结肠炎通过本提案中描述的实验，我们希望继续这些研究，以阐明（i）宿主细胞1整合素和1整合素介导的信号事件如何与Y相互作用。小肠结肠炎（特别是侵袭素蛋白和耶尔森氏菌粘附素A）促进Yop注射到不同的宿主细胞类型中，和（ii）在实验小鼠体内感染中被Yop注射的宿主细胞（树突细胞、B和T细胞）实际上如何影响它们的免疫功能。这将通过Y来实现。包括α-内酰胺酶报告系统的小肠结肠炎突变菌株，以及用突变的β 1整联蛋白感染细胞系和小鼠。这些研究的结果将增加对TTSS如何在细菌感染中起作用的理解，并可能为抑制TTSS或利用TTSS作为疫苗或治疗剂的递送系统的新型治疗策略提供分子基础。

Many pathogenic bacteria express type three secretion systems (TTSS) by which they inject toxins into host cells in order to evade defense mechanisms of the host. An important virulence mechanism of pathogenic Yersinia enterocolitica is to inject by a TTSS Yersinia outer proteins (Yops) into host cells. A -lactamase reporter system for tracking Yop injection allowed us to gain new insights into Yop injection by Y. enterocolitica. By means of the experiments described in this proposal we want to pursue these studies in order to elucidate (i) how host cell 1 integrins and 1 integrin-mediated signalling events upon interaction with Y. enterocolitica (particularly invasin protein and Yersinia adhesin A) facilitate Yop injection into different host cell types, and (ii) how host cells (dendritic cells, B and T cells) that are injected by Yops in experimental mouse infection in vivo are actually affected in their immunological functions. This will be accomplished by means of Y. enterocolitica mutant strains including a -lactamase reporter system, and infection of cell lines as well as mice with mutated 1 integrins. The results of these investigations will increase the understanding on how TTSS act in bacterial infections and might provide a molecular basis for novel therapeutic strategies to inhibit TTSS or to take advantage of TTSS as delivery systems for vaccines or therapeutics.