title: HLA-DO transduced in human monocyte-derived dendritic cells modulates MHC class II antigen processing.
abstract: Through the regulation of human leukocyte antigen (HLA)-DM (DM) in B cells, HLA-DO (DO) modulates positively or negatively the presentation of specific peptides. Transduction of DO into human blood monocyte-derived dendritic cells (MoDC) has been proposed as a mean of modifying the peptide repertoire of major histocompatibility complex class II molecules. However, maturation of DC induced by inflammatory stimuli or possibly the adenoviral vector itself triggers acidification of vesicles and shuts down transcription of the class II transactivator gene as well as de novo biosynthesis of class II-related molecules and DM activity. In these conditions, it is unclear that transduced DO could alter the peptide repertoire. Our Western blot and reverse transcriptase-polymerase chain reaction analyses revealed that human DC derived from blood monocytes express small amounts of DOalpha. Transduction of DObeta alone resulted in the accumulation of a small pool of DO in DM(+) CD63(+) vesicles and at the plasma membrane of mature DC. The cell-surface increase in class II-associated invariant chain peptide (CLIP)/class II complexes is in line with an inhibitory role of DO on DM. Cotransduction of DOalpha and DObeta only slightly increased CLIP and DO levels at the cell surface. Together with the fact that a large fraction of transduced DO remains in the endoplasmic reticulum, this suggests that DM is limiting in these conditions. DO expression did not affect a mixed lymphocyte reaction but reduced presentation of the exogenous gp100 antigen to a specific T cell clone. These results show that transduced DO modulates antigen presentation in human mature MoDC, evoking the possible use of this chaperone for immunotherapy.
authors.affiliation: Laboratoire d'Immunologie Moléculaire, Département de Microbiologie et Immunologie, Université de Montréal, CP 6128, Québec, Canada.
authors.forename: Angélique
authors.initials: A
authors.lastname: Bellemare-Pelletier
authors.forename: Jessy
authors.initials: J
authors.lastname: Tremblay
authors.forename: Sylvie
authors.initials: S
authors.lastname: Beaulieu
authors.forename: Mohamed-Rachid
authors.initials: MR
authors.lastname: Boulassel
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Routy
authors.forename: Bernard
authors.initials: B
authors.lastname: Massie
authors.forename: Réjean
authors.initials: R
authors.lastname: Lapointe
authors.forename: Jacques
authors.initials: J
authors.lastname: Thibodeau
mesh_terms: D017951:Antigen Presentation / Q000235:genetics* / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D022162:Cytoplasmic Vesicles / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000276:immunology; D006681:HLA-D Antigens / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008562:Membrane Glycoproteins / Q000276:immunology; D018832:Molecular Chaperones / Q000276:immunology; D009000:Monocytes / Q000276:immunology / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000276:immunology; D013601:T-Lymphocytes; D014161:Transduction, Genetic; D058951:gp100 Melanoma Antigen
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D006681:HLA-D Antigens; C084245:HLA-DM antigens; C046148:HLA-DO antigens; D000949:Histocompatibility Antigens Class II; D008562:Membrane Glycoproteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen; C045084:invariant chain