Identificaiton of Novel Immunogenic Human Papillomavirus Type 16 E7-Specific Epitopes Restricted to HLA-A*33;03 for Cervical Cancer Immunotherapy

Yonsei Med J. 2017 Jan;58(1):43-50. doi: 10.3349/ymj.2017.58.1.43.

Abstract

Purpose: To identify new immunogenic HLA-A*33;03-restricted epitopes from the human papillomavirus (HPV) 16 E7 protein for immunotherapy against cervical cancer.

Materials and methods: We synthesized fourteen overlapping 15-amino acid peptides and measured intracellular interferon-γ (IFN-γ) production in PBMC and CD8+ cytotoxic T lymphocytes (CTLs) after sensitization with these peptides using flow cytometry and ELISpot assay. The immunogenicity of epitopes was verified using a ⁵¹Cr release assay with SNU1299 cells.

Results: Among the fourteen 15-amino acid peptides, E7₄₉₋₆₃ (RAHYNIVTFCCKCDS) demonstrated the highest IFN-γ production from peripheral blood mononuclear cells (PBMCs), and CD8+ CTLs sensitized with E7₄₉₋₆₃ showed higher cytotoxic effect against SNU1299 cells than did CD8+ CTLs sensitized with other peptides or a negative control group. Thirteen 9- or 10-amino acid overlapping peptides spanning E7₄₉₋₆₃, E7₅₀₋₅₉ (AHYNIVTFCC), and E7₅₂₋₆₁ (YNIVTFCCKC) induced significantly higher IFN-γ production and cytotoxic effects against SNU1299 cells than the other peptides and negative controls, and the cytotoxicity of E7₅₀₋₅₉- and E7₅₂₋₆₁-sensitized PBMCs was induced via the cytolytic effect of CD8+ CTLs.

Conclusion: We identified E7₅₀₋₅₉ and E7₅₂₋₆₁ as novel HPV 16 E7 epitopes for HLA-A*33;03. CD8+ CTL sensitized with these peptides result in an antitumor effect against cervical cancer cells. These epitopes could be useful for immune monitoring and immunotherapy for cervical cancer and HPV 16-related diseases including anal cancer and oropharyngeal cancer.

Keywords: HLA-A*33;03; HPV 16 E7; cervical cancer; epitopes; immunotherapy.

MeSH terms

  • Amino Acid Sequence
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / metabolism
  • Epitopes / immunology*
  • Epitopes / therapeutic use
  • Female
  • HLA-A Antigens*
  • Human papillomavirus 16 / immunology*
  • Humans
  • Immunotherapy*
  • Interferon-gamma / analysis
  • Interferon-gamma / biosynthesis*
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / metabolism
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / metabolism
  • Uterine Cervical Neoplasms / therapy*

Substances

  • Epitopes
  • HLA-A Antigens
  • HLA-A*33 antigen
  • Interferon-gamma