Human_colon_16S

The human colon contains an extensively diverse microbial ecosystem. The colon immune system interacts closely with this ecosystem, ensuring tolerance in times of 'peace' yet potently reacting against pathogens that cause disease. Studies have highlighted dynamic crosstalk between immune cells and commensals. In particular, germ-free mice colonised with human microbiota have shown at a molecular level (with traditional flow-cytometry) that specific species can induce specific immune cell responses, particularly from T cells (1-4). While studies have demonstrated increasing diversity of microbiota from stomach to stool (5-7), whether and how immune cell heterogeneity and microbiota diversity change across the colon is undefined. Furthermore, whether these changes are co-depended in the healthy colon is unknown. The overarching aims of this study are: 1. Create an in-depth reference map of the changing microbiome across healthy human colons. 2. Assess at single-cell resolution T cell and myeloid cell phenotypes within the same colon tissues. 3. Determine whether the changes in microbiome and immune cell profiles with the colon are co-dependent, and demonstrate such relationships, though the intelligent application of human-gnotobiotic mice.