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

TCRαβ+CD8αα+ Intraepithelial lymphocytes (IELs) are abundant in the 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.