Activated human γδ T cells induce peptide-specific CD8+ T-cell responses to tumor-associated self-antigens

Cancer Immunol Immunother. 2012 Mar;61(3):385-96. doi: 10.1007/s00262-011-1111-6. Epub 2011 Sep 18.

Abstract

Specific cellular immunotherapy of cancer requires efficient generation and expansion of cytotoxic T lymphocytes (CTLs) that recognize tumor-associated self-antigens. Here, we investigated the capacity of human γδ T cells to induce expansion of CD8+ T cells specific for peptides derived from the weakly immunogenic tumor-associated self-antigens PRAME and STEAP1. Coincubation of aminobisphosphonate-stimulated human peripheral blood-derived γδ T cells (Vγ9+Vδ2+), loaded with HLA-A*02-restricted epitopes of PRAME, with autologous peripheral blood CD8+ T cells stimulated the expansion of peptide-specific cytolytic effector memory T cells. Moreover, peptide-loaded γδ T cells efficiently primed antigen-naive CD45RA+ CD8+ T cells against PRAME peptides. Direct comparisons with mature DCs revealed equal potency of γδ T cells and DCs in inducing primary T-cell responses and peptide-specific T-cell activation and expansion. Antigen presentation by γδ T-APCs was not able to overcome the limited capacity of peptide-specific T cells to interact with targets expressing full-length antigen. Importantly, T cells with regulatory phenotype (CD4+ CD25hiFoxP3+) were lower in cocultures with γδ T cells compared to DCs. In summary, bisphosphonate-activated γδ T cells permit generation of CTLs specific for weakly immunogenic tumor-associated epitopes. Exploiting this strategy for effective immunotherapy of cancer requires strategies that enhance the avidity of CTL responses to allow for efficient targeting of cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / immunology
  • Antigens, Neoplasm / genetics
  • Antigens, Neoplasm / immunology
  • Autoantigens / genetics
  • Autoantigens / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Line, Tumor
  • Cell Proliferation
  • Cells, Cultured
  • Coculture Techniques
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism
  • Diphosphonates / pharmacology
  • Epitopes, T-Lymphocyte / immunology
  • Flow Cytometry
  • HLA-A2 Antigen / immunology
  • Humans
  • Imidazoles / pharmacology
  • K562 Cells
  • Lymphocyte Activation / drug effects
  • Lymphocyte Activation / immunology
  • Neoplasms / genetics
  • Neoplasms / immunology
  • Neoplasms / pathology
  • Oxidoreductases / genetics
  • Oxidoreductases / immunology
  • Peptides / genetics
  • Peptides / immunology
  • Receptors, Antigen, T-Cell, alpha-beta / immunology*
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / metabolism
  • Transfection
  • Zoledronic Acid

Substances

  • Antigens, Neoplasm
  • Autoantigens
  • Diphosphonates
  • Epitopes, T-Lymphocyte
  • HLA-A*02 antigen
  • HLA-A2 Antigen
  • Imidazoles
  • PRAME protein, human
  • Peptides
  • Receptors, Antigen, T-Cell, alpha-beta
  • Zoledronic Acid
  • Oxidoreductases
  • STEAP1 protein, human