MELOE-1 antigen contains multiple HLA class II T cell epitopes recognized by Th1 CD4+ T cells from melanoma patients

PLoS One. 2012;7(12):e51716. doi: 10.1371/journal.pone.0051716. Epub 2012 Dec 20.

Abstract

MELOE-1 is an overexpressed melanoma antigen containing a HLA-A2 restricted epitope, involved in melanoma immunosurveillance of patients adoptively transferred with tumour infiltrating lymphocytes (TIL). The use of the full-length antigen (46 aa) for anti-melanoma vaccination could be considered, subject to the presence of Th epitopes all along MELOE-1 sequence. Thus, in this study we evaluated in vitro the immunoprevalence of the different regions of MELOE-1 (i.e. their ability to induce CD4 T cell responses in vitro from PBMC). Stimulation of PBMC from healthy subjects with MELOE-1 induced the amplification of CD4 T cells specific for various regions of the protein in multiple HLA contexts, for each tested donor. We confirmed these results in a panel of melanoma patients, and documented that MELOE-1 specific CD4 T cells, were mainly Th1 cells, presumably favourable to the amplification of CD8 specific T cells. Using autologous DC, we further showed that these class II epitopes could be naturally processed from MELOE-1 whole protein and identified minimal epitopes derived from each region of MELOE-1, and presented in four distinct HLA contexts. In conclusion, vaccination with MELOE-1 whole polypeptide should induce specific Th1 CD4 responses in a majority of melanoma patients, stimulating the amplification of CD8 effector cells, reactive against melanoma cells.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, Neoplasm / immunology*
  • Antigens, Neoplasm / metabolism
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / metabolism
  • Case-Control Studies
  • Cytokines / metabolism
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism
  • Epitopes, T-Lymphocyte / immunology*
  • Epitopes, T-Lymphocyte / metabolism
  • Flow Cytometry
  • Histocompatibility Antigens Class II / immunology*
  • Histocompatibility Antigens Class II / metabolism
  • Humans
  • Melanoma / immunology*
  • Melanoma / metabolism
  • Molecular Sequence Data
  • Neoplasm Proteins / immunology*
  • Neoplasm Proteins / metabolism
  • Peptide Fragments / immunology
  • T-Lymphocytes, Helper-Inducer / immunology*
  • T-Lymphocytes, Helper-Inducer / metabolism

Substances

  • Antigens, Neoplasm
  • Cytokines
  • Epitopes, T-Lymphocyte
  • Histocompatibility Antigens Class II
  • MELOE-1 antigen, human
  • Neoplasm Proteins
  • Peptide Fragments

Grants and funding

This work was supported by a grant from Inserm-transfer (Maturation/proof of concept projects). Mathilde Bobinet was supported by the Ligue Regionale contre le cancer (comité 85). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.