Combination effect of human B7-2 and dentric cells vaccines in anti-esophageal cancer in vitro

AIM: To investigate the roles of human B7-2 combined with dentric cell (DC) vaccine in inducing anti-tumor immunity against esophageal cancer in vitro. METHODS: Human esophageal cancer cell line EC9706 was transfected with the vector of pEGFP-N3-B7-2 by lipofectamine method. The mononuclear cells (MNCs) were separated from cord blood by density gradient centrifugation (Ficall-Hypaque) and then were induced to differentiate by cell factors. On the 3^rd day, EC9706 cytolysis antigen was added into the medium, in which DCs gradually matured and expressed special tumor antigen. After the matured DCs were co-cultured with autologous T cells derived from cord blood for 3 days, the T cells were activated to become tumor specific cytotoxic T lymphocytes (CTL). The inhibition of CTL on the transfected and untransfected EC9706 cells was detected by methyl thiazolyl tetrazolium (MTT) assay. RESULTS: The EGFP-B7-2 fusion gene was expressed mainly on the membrane of EC9706 cells, which proved the transfection was successful. Mature DCs with tumor cytolysis antigene was able to activate naive T cells to become tumor specialized CTL, and the CTL had significant inhibitory effect or killing response on EC9706 cells transfected with pEGFP-N3-B7-2(F = 21.672, P = 0.000). CONCLUSION: The human B7-2 combined with DC vaccine can induce significant killing response on esophageal cancer cell.