Intrinsic Defense Mechanisms of the Intestinal Epithelium Deepshika Ramanan, Ken Cadwell  Cell Host & Microbe  Volume 19, Issue 4, Pages 434-441 (April 2016) DOI: 10.1016/j.chom.2016.03.003 Copyright © 2016 Elsevier Inc. Terms and Conditions

Figure 1 Specialized Epithelial Cell Lineages Promote Barrier Protection in the Small Intestine Stem cells located in the crypts give rise to IECs with specialized function. Enterocytes predominate the single layer epithelium and participate in the exchange of nutrients. Paneth cells reside in the base of the crypts and secrete antimicrobial peptides, while other types of IECs migrate up the crypt-villus axis. Goblet cells produce mucins that form a physical barrier against invading pathogens and microbionts. Tuft cells secrete cytokines that help initiate immune responses to parasites. M cells line the Peyer’s patches and mediate transport of luminal antigens and bacteria to dendritic cells that initiate B and T cell responses, including production of a diverse repertoire of IgA by plasma cells in the lamina propria, the underlying connective tissue. IECs then transport IgA to the lumen with the pIgR. IECs also stimulate cytokine production by ILCs in response to adherent microbionts such as SFB, and produce many inflammatory mediators. The function of enteroendocrine cells (which secrete hormones) and other IECs like cup cells in host defense requires investigation. Cell Host & Microbe 2016 19, 434-441DOI: (10.1016/j.chom.2016.03.003) Copyright © 2016 Elsevier Inc. Terms and Conditions