Foxp3+ regulatory T cells (Tregs) are key players for the maintenance of tolerance against self and harmless exogenous antigens, such as the intestinal microbiota. Microbiota-specific Tregs therefore represent powerful targets for novel and specific therapies in inflammatory bowel disease (IBD). We have developed technologies to identify and characterize human microbiota-specific Tregs. We will screen for important Treg targets, isolate and expand Tregs with relevant specificities and analyze their functional characteristics as a basis for development of tailor-made Treg for IBD therapy.