Induction of antigen‑specific cytotoxic T-cell response by dendritic cells generated from ecto-mesenchymal stem cells infected with an adenovirus containing the MAGE-D4a gene

Abstract

The present study aimed to investigate the feasi­bility of using ecto‑mesenchymal stem cell (EMSC)‑derived dendritic cells (DCs) for glioma immunotherapy following infection by a recombinant adenovirus containing the melanoma‑associated antigen D4a (MAGE‑D4a) gene. The ex vivo cultured EMSCs were infected by the adenoviral plasmid containing MAGE‑D4a (pAd/MAGE‑D4a). Effi­ciency of transfection was evaluated through the detection of green fluorescent protein‑marked MAGE‑D4a. The MAGE‑EMSCs were induced to differentiate into DCs, termed as MAGE‑EMSCs‑DCs. The morphology was subsequently analyzed under a microscope, and methyl thiazolyl tetrazo­lium (MTT) and interferon‑γ (IFN‑γ) assays were performed to analyze the cytotoxicity of the MAGE‑EMSC‑DCs on the human glioma U251 cell line. Following purification by magnetic‑activated cell sorting, the EMSCs grew into swirls, with a long spindle shape and were fibroblast‑like. The gene transfected with recombinant adenovirus vectors maintained high and stable expression levels of MAGE‑D4a, and its effi­ciency was increased in a multiplicity of infection‑dependent manner. The results of the MTT assay indicated that the T cells, primed by the recombinant MAGE‑D4a‑infected EMSC‑DCs in vitro, recognized MAGE‑D4a‑expressing tumor cell lines in a human leukocyte antigen class I‑restricted manner, and evoked a higher cytotoxic T cell (CTL) response. The CTL response induced by the MAGE‑EMSC‑DCs, co‑cultured with the U251 cells for 24 h, produced 765.0 pg/ml IFN‑γ, which was significantly greater when compared to the control wells. T lymphocytes stimulated by MAGE‑EMSC‑DCs evoke a higher CTL response to human glioma cell lines, and may serve as a promising therapeutic modality for the treatment of MAGE‑D4a‑expressing glioma.