title: CD8αα TCRαβ Intraepithelial Lymphocytes in the Mouse Gut.
abstract: The epithelium of the mouse small intestine harbors an abundant CD8αα(+)TCRαβ(+) intraepithelial lymphocyte (IEL) population. This unique IEL subset is a self-reactive population that requires exposure to self-agonists for selection in the thymus, similarly to other regulatory T cell populations. After leaving the thymus, these cells directly seed the intestinal epithelium, which provides a unique combination of cellular interactions together with cytokines, nutrients, and antigens that guide the lineage-specific differentiation and function of these IELs. For instance, epithelial cells and nearby immune cells secrete a number of cytokines, including interleukin-15 (IL-15), IL-7, and transforming growth factor-β, resulting in an assortment of cellular responses, including activation of master transcription factors, cell proliferation, and cytokine secretion. Recent advances have also highlighted the importance of diet-derived substances and commensal metabolites, such as the aryl hydrocarbon receptor ligands and vitamin D, in controlling the survival and gene expression of CD8αα(+)TCRαβ(+) IELs. Furthermore, these cells function in the epithelium and require constant communication between cells in the form of cell-to-cell contacts. These interactions tune the antigen sensitivity of the TCR and maintain the quiescence of the CD8αα(+)TCRαβ(+) IELs. Finally, we discuss how these cells might contribute to tolerance and immunopathological responses in the gut. Therefore, an increased understanding of CD8αα(+)TCRαβ(+) IELs in the gut will help us understand how these cells participate in immune regulation and protection.
authors.affiliation: Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Shapingba, Chongqing, 400037, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Shapingba, Chongqing, 400037, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Peng
authors.affiliation: Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Shapingba, Chongqing, 400037, China.
authors.forename: Minqiang
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Shapingba, Chongqing, 400037, China. m18523912037@163.com.
authors.forename: Weidong
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Shapingba, Chongqing, 400037, China. huayang@tmmu.edu.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000235:genetics / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000166:cytology*; D007413:Intestinal Mucosa / Q000166:cytology*; D008214:Lymphocytes / Q000502:physiology*; D051379:Mice; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain; D016693:Receptors, Antigen, T-Cell, alpha-beta
keywords: Aryl hydrocarbon receptor; CD8αα; Cytokine; Intraepithelial lymphocytes; Vitamin D receptor