Purpose: Carcinoembryonic antigen (CEA) is a candidate target for cellular immunotherapy of pancreatic cancer. In this study, we have characterized the antigen-specific function of autologous cytotoxic T lymphocytes (CTL) specific for the HLA-A2-restricted peptide, pCEA691-699, isolated from the peripheral T-cell repertoire of pancreatic cancer patients and sought to determine if ex vivo PD-L1 and TIM-3 blockade could enhance CTL function.Experimental Design: CD8+ T-cell lines were generated from peripheral blood mononuclear cells of 18 HLA-A2+ patients with pancreatic cancer and from 15 healthy controls. In vitro peptide-specific responses were evaluated by flow cytometry after staining for intracellular cytokine production and carboxy fluorescein succinimydyl ester cytotoxicity assays using pancreatic cancer cell lines as targets.Results: Cytokine-secreting functional CEA691-specific CTL lines were successfully generated from 10 of 18 pancreatic cancer patients, with two CTL lines able to recognize and kill both CEA691 peptide-loaded T2 cells and CEA+ HLA-A2+ pancreatic cancer cell lines. In the presence of ex vivo PD-L1 blockade, functional CEA691-specific CD8+ T-cell responses, including IFNγ secretion and proliferation, were enhanced, and this effect was more pronounced on Ag-specific T cells isolated from tumor draining lymph nodes.Conclusions: These data demonstrate that CEA691-specific CTL can be readily expanded from the self-restricted T-cell repertoire of pancreatic cancer patients and that their function can be enhanced by PD-L1 blockade. Clin Cancer Res; 23(20); 6178-89. ©2017 AACR.
Clin Cancer Res
6178 - 6189
Adult, Aged, Aged, 80 and over, Antineoplastic Agents, Immunological, B7-H1 Antigen, Biomarkers, Tumor, Carcinoembryonic Antigen, Cell Line, Tumor, Cytokines, Cytotoxicity, Immunologic, Female, Hepatitis A Virus Cellular Receptor 2, Humans, Immunophenotyping, Male, Middle Aged, Neoplasm Staging, Pancreatic Neoplasms, Programmed Cell Death 1 Receptor, Signal Transduction, T-Cell Antigen Receptor Specificity, T-Lymphocyte Subsets, T-Lymphocytes, Cytotoxic