Dendritic cell-glioma fusion activates T lymphocytes by elevating cytotoxic efficiency as an antitumor vaccine

BACKGROUND Hybrid cells produced by fusions of tumor and dendritic cells (DC) have demonstrated remarkable efficacy for priming the anti-tumor immune response. In the current study, we examined the antitumor activity of cytotoxic T lymphocytes (CTLs) primed in response to a tumor vaccine comprising a glioma-DC fusion as part of a therapeutic against glioma. MATERIAL AND METHODS Primary cultured glioma cells were fused with peripheral blood DC under conditions of polyethylene glycol (PEG) incubation. Glioma cell suspensions were designated as three groups to include (1) CTL-effective cell group activated by fused cells; (2) CTL-effective cell group stimulated by co-cultured glioma cells and DC cells; and (3) lymphocyte-only group as a control, which was not stimulated by the DC. Cytotoxicity of CTLs on glioma cells was accessed by MTT assay in vitro. RESULTS Glioma cells with peripheral blood DC were cultured and fused. The killing effect of CTLs pre-activated by fused cells was significantly higher than that of the co-culture CTL group with unsensitized lymphocytes (p < 0.01). The killing activity, as measured by an enhanced efficiency ratio, was increased significantly in the co-cultures of fused cells with CTL groups (p < 0.01). CONCLUSIONS The glioma-dendritic cell fusion vaccine possessed a more effective anticancer activity by stimulating the effector activity of CTLs.