The zymogen granule membrane glycoprotein 2 (GP2) as trigger for host tropism and individuality of intestinal infections.

酶原颗粒膜糖蛋白2(GP2)由肠道滤泡相关上皮细胞表达，通过与细菌粘附素FimH结合影响肠道感染，可能在Crohns病中起作用，是天然免疫和获得性免疫的免疫调节剂。在我们以前利用肠杆菌科的工作中，我们发现与GP2的结合是单一细菌或病原菌类型所特有的，也是宿主动物物种所特有的。在我们全面的前期工作的基础上，我们想通过以下假设来详细阐明这种现象的机制：细菌肠道感染通常是宿主特异性的和个体的。GP2及其与细菌的相互作用以及通过肠道上皮细胞对肠道免疫系统细胞的影响是宿主趋向性和个性化的基础。在我们的初步工作中，我们只使用了所描述的四种人类GP2亚型中的一种。由于其他哺乳动物的GP2尚不清楚，我们将定义其他哺乳动物的GP2，包括可能的异构体。比较了GP2和GP2亚型。为了鉴定新的GP2，我们从已发表的DNA序列中筛选出与GP2同源的序列，或者使用猪或牛的组织来产生cDNA。已鉴定的GP2类型和异构体被重组表达。我们使用GP2蛋白和400个明确定义的细菌分离物以筛选形式进行结合研究。同时，我们转导细胞系在宿主特定的背景下表达每一种GP2亚型。这些细胞用于黏附和侵袭研究。此外，吞噬细胞的细胞系与荧光标记的细菌孵育(吞噬试验)。最后，我们首先进行体外感染研究，以显示重组GP2是否可以抑制细菌感染。

The zymogen granule membrane glycoprotein 2 (GP2) is expressed by the follicle associated epithelium of the intestine, affects intestinal infections via binding of the bacterial adhesin FimH, might play a role in Crohns disease and is an immunomodulator of the innate as well as acquired immunity. In our previous work using Enterobacteriaceae we showed that binding to GP2 is specific for single bacterial species or pathotypes but also specific for host animal species.Based upon our comprehensive preliminary work we would like to clarify in detail mechanisms of this phenomenon by means of the following hypothesis: bacterial intestinal infections are often host specific and individual. GP2 and its interactions with bacteria on the one hand and effects via intestinal epithelial cells to cells of the intestinal immune system on the other hand are basics for host tropism and individuality.In our preliminary work we used only one out of four described human GP2 isoforms. Since GP2 of other mammal species is unknown yet, we will define other mammal GP2 including possible isoforms. GP2 and GP2 isoforms are compared to each other. For identification of new GP2 we screen published DNA sequences for sequences homologue to GP2 or use tissues of pigs or cattle to generate cDNA. Identified GP2 types and isoforms are recombinantly expressed. We perform binding studies in a screening format using GP2 proteins and 400 well defined bacterial isolates. In parallel, we transduce cell lines to express each GP2 isoform in its host specific background. These cells are used for adhesion and invasion studies. In addition, cell lines of phagocytes are incubated with fluorescence labelled bacteria (phagocytosis assays). Finally, we perform first in vitro infection studies to show whether recombinant GP2 can inhibit bacterial infections.