An HLA-DR-degenerate epitope pool detects insulin-like growth factor binding protein 2-specific immunity in patients with cancer

Cancer Res. 2008 Jun 15;68(12):4893-901. doi: 10.1158/0008-5472.CAN-07-6726.

Abstract

Recent studies have shown the importance of helper CD4 T cells in initiating and sustaining tumor-specific CD8 T-cell immunity. This has paved the way for identifying MHC class II epitopes that could be incorporated into class I-based vaccines. In this study, the goal was to identify an HLA-DR-degenerate epitope pool derived from insulin-like growth factor binding protein 2 (IGFBP-2). IGFBP-2, a regulator of insulin-like growth factor action, is overexpressed in the majority of breast and ovarian cancers. Using algorithms, we predicted 29 HLA-DR1-binding epitopes. Binding assays targeting 15 different HLA-DRs revealed that 10 epitopes were degenerate, binding to at least four different HLA-DR variants. An IFN-gamma enzyme-linked immunosorbent spot assay was used to assess immunity to these 10 epitopes in 48 patients with either breast or ovarian cancer and 18 controls. Elevated T-cell immunity in patients was detected in 4 of the 10 epitopes (IGFBP2.17, IGFBP2.22, IGFBP2.249, and IGFBP2.293). The cumulative T-cell frequency of these four epitopes was elevated in patients relative to controls. All four peptides are naturally processed and presented to CD4 T-cells. The degenerate pool of peptides covers nearly 80% of patients and may be useful for augmenting CD4 T-cell immunity in patients undergoing immunization.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism
  • Case-Control Studies
  • Dendritic Cells / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes
  • HLA-DR1 Antigen / genetics*
  • HLA-DR1 Antigen / immunology*
  • Humans
  • Insulin-Like Growth Factor Binding Protein 2 / immunology*
  • Insulin-Like Growth Factor Binding Protein 2 / metabolism
  • Neoplasms / immunology*
  • Peptide Fragments / immunology
  • Peptide Fragments / metabolism

Substances

  • Epitopes
  • HLA-DR1 Antigen
  • Insulin-Like Growth Factor Binding Protein 2
  • Peptide Fragments