Commensal Bacteria-Dependent CD8??+ T Cells in the Intestinal Epithelium Produce Antimicrobial Peptides.

ABSTRACT: The epithelium of the intestine functions as the primary "frontline" physical barrier for protection from enteric microbiota. Intraepithelial lymphocytes (IELs) distributed along the intestinal epithelium are predominantly CD8+ T cells, among which CD8??+ IELs are a large population. In this investigation, the proportion and absolute number of CD8??+ IELs decreased significantly in antibiotic-treated and germ-free mice. Moreover, the number of CD8??+ IELs was correlated closely with the load of commensal microbes, and induced by specific members of commensal bacteria. Microarray analysis revealed that CD8??+ IELs expressed a series of genes encoding potent antimicrobial peptides (AMPs), whereas CD8??+ splenocytes did not. The antimicrobial activity of CD8??+ IELs was confirmed by an antimicrobial-activity assay. In conclusion, microbicidal CD8??+ IELs are regulated by commensal bacteria which, in turn, secrete AMPs that have a vital role in maintaining the homeostasis of the small intestine.

SUBMITTER: Chen B 

PROVIDER: S-EPMC5964211 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature