OBJECTIVETo study the biological characteristics of cytotoxicity T lymphocyte (CTL) induced by dendritic cell (DC) transfected with the Epstein-Barr virus latent membrane protein 2A (EBV-LMP2A) recombinant adenovirus. To establish nasopharyngeal carcinoma (NPC) animal models expressing LMP2A and investigate the anti-tumor effect of LMP2A specific CTL in vivo.

METHODSThe mononuclear cells were isolated from human peripheral blood mononuclear cells (PBMC) and cultured with the cytokines [granulocyto-monocyte colony stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor-alpha TNF-alpha]. The expression of surface markers on mature DC was detected by fluorescence activated cell sorter FACS. Mature DC were transfected with LMP2A recombinant adenovirus. Under the help of interleukin-2 (IL-2), LMP2A specific CTL were induced by coculturing LMP2A-transfected DC with autologous PBMC. The population of CTL was detected by FACS. NPC animal models were constructed by implanting CNE cells expressing LMP2A subcutaneously into BALB/c nude mice. After intra-tumoral injection of LMP2A specific CTL, the size of tumor was measured. The tumors were removed after 30 d and subjected to histological examination.

RESULTSMature DC displaying typical characteristics of morphology and phenotype were obtained from monocytes cultured in the medium containing GM-CSF, IL-4 and TNF-alpha. The LMP2A specific CTL induced by transfected DC were composed of mainly CD4+ and CD8+ T cells. The NPC animal models were constructed three weeks after implanting CNE cells. The study in vivo indicated that the tumors treated with LMP2A specific CTL grew slowly compared with control. Tumor volume of treated groups was significantly smaller than that of controls. The histological sections showed local necrosis and infiltration of lymphocyte in tumor tissue.

CONCLUSIONSTypically mature DC could be generated in vitro by culturing monocytes with the cytokines. LMP2A-specific CTL could be induced by LMP2A transfected DC in vitro. NPC mice models could be constructed by implanting CNE cells. LMP2A specific CTL could inhibit the growth of implanted tumor and produce an anti-tumor effect in vivo.