The human gut is home to the densest accumulation of microbes on earth and the last 2 decades have revealed that our immune system actively engages with these mostly beneficial inhabitants. CD4 T cells are induced by non-pathogenic gut bacteria and critically contribute to maintaining homeostasis. How they can become dysregulated and drive chronic aberrant inflammation such as in inflammatory bowel disease (IBD) has remained poorly understood.
In the Zimmermann lab, we harness novel gnotobiotic and immunological tools to understand the regulation of CD4 T cells induced by the gut microbiota. We have developed bacterial mutants that only transiently colonise germ-free mice to disconnect the induction of CD4 T cell responses from the persistence of cognate antigen. We can trace CD4 T cells that were induced by such a transient gut colonisation through state-of-the-art immunological approaches to understand how they contribute to barrier protection and how they might drive IBD when dysregulated. We envision that our work might aid mucosal vaccination approaches and identify novel therapeutic targets in IBD. To improve diagnostics, we develop novel sequencing- and cytometry-based methods to interrogate the gut microbiota.
We are grateful for funding by an ERC & SNSF Starting Grant, the Bern Center for Precision Medicine, and the Novartis foundation.
