Cancer associated aberrant protein O-glycosylation can modify antigen processing and immune response

PLoS One. 2012;7(11):e50139. doi: 10.1371/journal.pone.0050139. Epub 2012 Nov 26.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylgalactosamine / metabolism
  • Amino Acid Sequence
  • Animals
  • Antibody Specificity / immunology
  • Antigen Presentation / immunology*
  • Antigens, Neoplasm / immunology
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Line
  • Glycosylation
  • Histocompatibility Antigens Class I / immunology
  • Histocompatibility Antigens Class I / metabolism
  • Immunoglobulin G / immunology
  • Lymphocyte Activation / immunology
  • Mice
  • Molecular Sequence Data
  • Mucin-1 / chemistry
  • Mucin-1 / immunology
  • Mucin-1 / metabolism
  • Neoplasms / immunology*
  • Neoplasms / metabolism*
  • Peptides / chemistry
  • Peptides / metabolism
  • Protein Binding / immunology

Substances

  • Antigens, Neoplasm
  • Histocompatibility Antigens Class I
  • Immunoglobulin G
  • Mucin-1
  • Peptides
  • Acetylgalactosamine

Grant support

This project was supported by the Novo Nordisk Foundation, the Danish Medical Research Council, the Danish Cancer Research Foundation, the Agnes and Poul Friis Foundation, the Danish Cancer Society, the University of Copenhagen (Program of Excellence), EU-FP7, Danish Agency for Science, and Technology and Innovation (FTP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.