title: Cancer associated aberrant protein O-glycosylation can modify antigen processing and immune response.
abstract: Aberrant glycosylation of mucins and other extracellular proteins is an important event in carcinogenesis and the resulting cancer associated glycans have been suggested as targets in cancer immunotherapy. We assessed the role of O-linked GalNAc glycosylation on antigen uptake, processing, and presentation on MHC class I and II molecules. The effect of GalNAc O-glycosylation was monitored with a model system based on ovalbumin (OVA)-MUC1 fusion peptides (+/- glycosylation) loaded onto dendritic cells co-cultured with IL-2 secreting OVA peptide-specific T cell hybridomas. To evaluate the in vivo response to a cancer related tumor antigen, Balb/c or B6.Cg(CB)-Tg(HLA-A/H2-D)2Enge/J (HLA-A2 transgenic) mice were immunized with a non-glycosylated or GalNAc-glycosylated MUC1 derived peptide followed by comparison of T cell proliferation, IFN-γ release, and antibody induction. GalNAc-glycosylation promoted presentation of OVA-MUC1 fusion peptides by MHC class II molecules and the MUC1 antigen elicited specific Ab production and T cell proliferation in both Balb/c and HLA-A2 transgenic mice. In contrast, GalNAc-glycosylation inhibited the presentation of OVA-MUC1 fusion peptides by MHC class I and abolished MUC1 specific CD8+ T cell responses in HLA-A2 transgenic mice. GalNAc glycosylation of MUC1 antigen therefore facilitates uptake, MHC class II presentation, and antibody response but might block the antigen presentation to CD8+ T cells.
authors.affiliation: Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Madsen
authors.forename: Cecilie
authors.initials: C
authors.lastname: Petersen
authors.forename: Kirstine
authors.initials: K
authors.lastname: Lavrsen
authors.forename: Mikkel
authors.initials: M
authors.lastname: Harndahl
authors.forename: Søren
authors.initials: S
authors.lastname: Buus
authors.forename: Henrik
authors.initials: H
authors.lastname: Clausen
authors.forename: Anders E
authors.initials: AE
authors.lastname: Pedersen
authors.forename: Hans H
authors.initials: HH
authors.lastname: Wandall
mesh_terms: D000116:Acetylgalactosamine / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D017951:Antigen Presentation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D006031:Glycosylation; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D009369:Neoplasms / Q000276:immunology* / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D018396:Mucin-1; D010455:Peptides; D000116:Acetylgalactosamine