An experimental study of dendritic cells-mediated immunotherapy against intracranial gliomas in rats

To investigate the effect of dendritic cells(DC) pulsed with apoptotic tumor cells for treatment of intracranial gliomas in rats.

C6 glioma cells were injected into brain of Wistar rats under stereotactic monitor to establish an animal model of glioma. The precursors of DCs were isolated from bone marrow of rats, stimulated in vitro with recombinent rat granulocyte-macrophage colony-stimulating factor (rrGM-CSF) and interleukin-4 (rrIL-4). These DCs were then pulsed ex vivo with apoptotic C6 glioma cells induced by heating and subsequently injected subcutaneously into rats harboring intracranial C6 glioma. Rats were treated with five weekly subcutaneous injections of either control media, unpulsed DCs, or DCs pulsed with apoptotic tumor cells. The animals were followed for survival, volume of tumor by MRI, CD8 + T cells, cytotoxicity assay in vitro and proliferational function of lymphocytes in peripheral blood were determined by flow cytometry(FCM). The concentration of cytokines interferon-gamma (IFN-gamma) and interleukin-10(IL-10) were monitored through enzyme-linked immunosorbent assay(ELISA) using ELISAkit.

Our results indicated that C6 glioma model rats treated with apoptotic tumor cells pulsed DCs prolonged survival, inhibited the tumor growth and increased the level of CD8 + T lymphocytes in peripheral blood comparing with control group. Cytotoxicity assay suggested that vaccination with these apoptotic cells pulsed DCs can induce cytotoxic T lymphocytes response against C6 tumor cells compared with control group. Furthermore, significantly enhanced IFN-gamma and reduced IL-10(even undetectable) were observed in peripheral blood of rats treated with pulsed-DCs. No evident autoimmune response were detected.

Our data demonstrated that systemic vaccination with DCs pulsed with apoptotic cells is a safe and effective immunotherapy for intracranial glioma.