Discovery of immunomodulatory gut microbes with MAGIC

项目总结 共生微生物对人类健康有着深远的影响。然而，共生的本质是 刺激和调节宿主免疫系统的微生物在很大程度上是未知的。因此， 这些微生物参与宿主免疫的机制尚不清楚。然而，用于研究的遗传工具 微生物区系的免疫效果目前还不可用。此外，目前还不清楚有多少人 微生物区系物种容易受到基因操纵。抗TCR转基因小鼠的建立 个体共生微生物是研究这种免疫反应的重要途径。然而， 针对数百种微生物群产生单独的TCRTG小鼠是一项艰巨的任务。 在这里，我们提出了一种替代方法，在该方法中，我们将使用单个TCRTG小鼠来跟踪T细胞 对大多数微生物区系的反应，并鉴定免疫调节共生物种。为了实现这个目标，我们 开发了一种通过原位接合或魔术来改变肠道微生物组的元基因组的方法。 MAGIC导致外源蛋白同时在广泛的微生物区系物种中表达。 我们将使用这个系统1)创建一个转基因共生微生物的生物库，这些微生物可以表达 免疫原性蛋白；2)鉴定和分离免疫原性共生体；3)表征所产生的 T细胞反应。

PROJECT SUMMARY Commensal microbes have profound effects on human health. However, the nature of the commensal microbes that stimulate and regulate the immune system of the host is largely unknown. Therefore, the mechanisms by which such microbes engage host immunity are unknown. However, genetic tools to study immune effects of the microbiota are currently not available. Moreover, it is unclear how many of the microbiota species are amenable to genetic manipulation. Generation of TCR transgenic mice against individual commensal microbes is an important approach to study such immune responses. However, generation of individual TCR Tg mice against the hundreds of microbiota species is a monumental task. Here, we propose an alternative approach, in which we will use a single TCR Tg mice to track T cell responses to most of the microbiota and identify immunomodulatory commensal species. To this goal we developed an approach for Metagenomic Alteration of Gut microbiome by In situ Conjugation, or MAGIC. MAGIC leads to expression of exogenous proteins in a broad range of microbiota species simultaneously. We will use this system to 1) create a biobank of genetically-modified commensal microbes that express immunogenic proteins; 2) identify and isolate immunogenic commensals and 3) characterize the generated T cell responses.