Commensal bacteria maintain a Qa-1b-restricted unconventional CD8+ T population in gut epithelium

Intestinal intraepithelial lymphocytes (IELs) are characterized by an unusual phenotype and developmental pathway, yet their specific ligands and functions remain largely unknown. Here by analysis of QFL T cells, a population of CD8+ T cells critical for monitoring the MHC I antigen processing pathway, we established that unconventional Qa-1b-restricted CD8+ T cells are abundant in intestinal epithelium. We found that QFL T cells showed a Qa-1b-dependent unconventional phenotype in the spleen and small intestine of naïve wild-type mice. The splenic QFL T cells showed innate-like functionality exemplified by rapid response to cytokines or antigens, while the gut population was refractory to stimuli. Microbiota was required for the maintenance, but not the initial gut homing of QFL T cells. Interestingly, monocolonization with Pediococcus pentosaceus, which expresses a peptide that cross-activated QFL T cells, was sufficient to maintain QFL T cells in the intestine. Thus, microbiota is cr..., The raw data were collected from flow cytometry analysis. The numbers were calculated in Excel., , # Commensal Bacteria Maintain a Qa-1b-restricted Unconventional CD8+ T Population in Gut Epithelium

## 1. Author Information

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A. Corresponding Author Contact Information

Name: Jian Guan

Institution: Department of Pathology and the Institute of Cell Engineering, Johns Hopkins University School of Medicine

Address: Baltimore, MD 21287 USA

Email: [e-mail]

B. Co-corresponding Author Contact Information

Name: Scheherazade Sadegh-Nasseri

Institution: Department of Pathology and the Institute of Cell Engineering, Johns Hopkins University School of Medicine

Address: Baltimore, MD 21287 USA

Email: [e-mail]
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2\. Information about funding sources that supported the collection of the data: This work was supported by grants R01AI130210, R37AI060040 and R01AI149341 from the National Institutes of Health to NS.

3\. DATA & FILE OVERVIEW

File name: RawData_Figure_SPF vs GF QFL-T

The file contains data acquired through flow cytometry for ana...