Identification and Regulation of TCRαβ(+)CD8αα(+) Intraepithelial Lymphocytes in Murine Oral Mucosa

TCRαβ(+)CD8αα(+) intraepithelial lymphocytes (IELs) are abundant in gastrointestinal (GI) tract and play an important role in regulation of mucosal immunity and tolerance in the gut. However, it is unknown whether TCRαβ(+)CD8αα(+) IELs exist in the oral mucosa and if yes, what controls their development. We here identified and characterized TCRαβ(+)CD8αα(+) IELs from the murine oral mucosa. We showed that the number and function of TCRαβ(+)CD8αα(+) IELs were regulated by TGF-β. We further revealed that oral TCRαβ(+)CD8αα(+) IELs could be altered under systemic inflammatory conditions and by antibiotic treatment at the neonatal age of the mice. Our findings have revealed a previously unrecognized population of oral IELs that may regulate oral mucosal immune responses.