Fig. 4.

The use of organoids for the study of epithelial innate immunity. Clockwise: Organoids have been generated from different segments of the gastrointestinal tract and have been shown to retain tissue identity. Organoids from patients can be stored in biobanks to enable research on specific pathologies such as IBD. Using culture modifications, the cells in organoids can also be directed towards specific cell identities, such as secretory cells, enterocytes and M cells. Because organoids retain the polarity of the cells, they also allow testing of apical and basal stimulation. For this, cells can be seeded in transwell systems. Organoids are a reductionist model, which is not in contact with microbial compounds under standard conditions but can be used to study infection with bacteria and viruses and to study interaction with immune cells in co-culture experiments. In the future, more complex models will also allow combinations of several organoid types in microfluidic lab-on-a-chip devices