Identification and Regulation of TCRαβCD8αα Intraepithelial Lymphocytes in Murine Oral Mucosa.

TCRαβCD8αα 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 TCRαβCD8αα IELs exist in the oral mucosa and if yes, what controls their development. We here identified and characterized TCRαβCD8αα IELs from the murine oral mucosa. We showed that the number and function of TCRαβCD8αα IELs were regulated by TGF-β. We further revealed that oral TCRαβCD8αα 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.