Abstract
Purpose of Review
This review will explore the contribution of intraepithelial lymphocytes (IELs) to mucosal innate immunity and highlight the similarities in IEL functional responses to bacteria, viruses, and protozoan parasite invasion.
Recent Findings
IELs rapidly respond to microbial invasion by activating host defense responses, including the production of mucus and antimicrobial peptides to prevent microbes from reaching the epithelial surface. During active infection, IELs promote epithelial cytolysis, cytokine and chemokine production to limit pathogen invasion, replication, and dissemination. Commensal-induced priming of IEL effector function or continuous surveillance of the epithelium may be important contributing factors to the rapidity of response.
Summary
Impaired microbial recognition, dysregulated innate immune signaling, or microbial dysbiosis may limit the protective function of IELs and increase susceptibility to disease. Further understanding of the mechanisms regulating IEL surveillance and sentinel function may provide insight into the development of more effective targeted therapies designed to reinforce the mucosal barrier.
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References
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Acknowledgements
This work is supported by funding from the National Institutes of Health K01 DK093627, R03 DK106484, and the Feldstein Medical Foundation (KLE). The authors would like to thank Dr. George Yap for his critical review of the manuscript.
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Madeleine Hu, Luo Jia, and Karen Edelblum declare that they have no conflict of interest.
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Hu, M.D., Jia, L. & Edelblum, K.L. Policing the Intestinal Epithelial Barrier: Innate Immune Functions of Intraepithelial Lymphocytes. Curr Pathobiol Rep 6, 35–46 (2018). https://doi.org/10.1007/s40139-018-0157-y
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DOI: https://doi.org/10.1007/s40139-018-0157-y