Table I. Examples illustrating the diverse immune functions of iIELs in disease
iIEL SubsetInfectionInflammation/ColitisCeliac DiseaseReferences
CD4+TCRαβ+Effector memoryPathogenicUnknown(29)
Th1 and Th17 responses against mucosal pathogens
CD4+CD8αα+TCRαβ+UnknownPossibly regulatory functions mediated by IL-10Unknown(107110)
CD8αβ+TCRαβ+Effector memory responses against mucosal pathogens, such as vesicular stomatitis virus and L. monocytogenesUnknownLyse IECs via NKG2D–MICA interactions(29, 32, 111, 115)
CD8αβ+CD8αα+TCRαβ+UnknownUnknownUnknown
CD8αα+TCRαβ+UnknownPossibly regulatory functions mediated by TGF-β3, Lag-3, IL-10Unknown(116118)
CD8αα+/−TCRγδ+Antimicrobial activity against pathogens, such as S. typhimurium, T. gondii, N. brasiliensis; RegIIIγ mediatedProinflammatory in early stages of murine colitis; promote healing and protect epithelial integrity in late stages of inflammation and colitisExpansion during disease but function is not well understood(15, 32, 118, 122125, 128136, 139, 140)
ILC1-likeUnknownCause IFN-γ–mediated pathology in anti–CD40 Ab–induced colitisUnknown(56, 58)
iCD8αPromote bacterial clearance of organisms, such as C. rodentium; phagocytic; capable of MHC class II–restricted Ag presentationDecreased numbers in necrotizing enterocolitis; promote intestinal inflammation via granzymesUnknown(17, 49)
iCD3+UnknownUnknownMay develop into lymphomas in some patients with refractory celiac disease(60, 141)
  • Lag-3, lymphocyte activating 3; MICA, MHC class I polypeptide-related sequence A.