title: The emerging role of HLA-E-restricted CD8+ T lymphocytes in the adaptive immune response to pathogens and tumors.
abstract: Human leukocyte antigen (HLA)-E is a nonclassical major histocompatibility complex (MHC) class I molecule of limited sequence variability that is expressed by most tissues albeit at low levels. HLA-E has been first described as the ligand of CD94/NKG2 receptors expressed mainly by natural killer (NK) cells, thus confining its role to the regulation of NK-cell function. However, recent evidences obtained by our and other groups indicate that HLA-E complexed with peptides can interact with alphabeta T-cell receptor (TCR) expressed on CD8(+) T cells. Although, HLA-E displays a selective preference for nonameric peptides, derived from the leader sequence of various HLA class I alleles, several reports indicate that it can present also "noncanonical" peptides derived from both stress-related and pathogen-associated proteins. Because HLA-E displays binding specificity for innate CD94/NKG2 receptors, as well as all the features of an antigen-presenting molecule, its role in both natural and acquired immune responses has recently been re-evaluated.
authors.affiliation: Dipartimento di Medicina Sperimentale and Centro di Eccellenza per le Ricerche Biomediche, Università degli Studi di Genova, 16132 Genova, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pietra
authors.forename: Chiara
authors.initials: C
authors.lastname: Romagnani
authors.forename: Claudia
authors.initials: C
authors.lastname: Manzini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Moretta
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Mingari
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D009164:Mycobacterium Infections / Q000276:immunology*; D009369:Neoplasms / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D014777:Virus Diseases / Q000276:immunology*; D000097625:HLA-E Antigens
chemical_list: D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D010455:Peptides; D016693:Receptors, Antigen, T-Cell, alpha-beta; D000097625:HLA-E Antigens