Objective To investigate the anticancer activity of dendritic cells(DC)transfected by recombinant adeno-associated virus(rAAV)-mediated carcinoembryonic antigen(CEA)gene in colorectal cancer treatment.Methods The recombinant plasmid rAAV/CEA was constructed and the rAAV/CEA virus stock was prepared.DC precursors were isolated from peripheral blood mononuclear cells(PBMC)by density gradient centrifugation and transfected with rAAV/CEA virus stock.The CEA expression,chromosome integration and efficiency of rAAV/CEA virus were determined by PCR,Southern blot and flow cytometery.DC precursor cells were induced by granulocyte macrophage colony-stimulating factor(GM-CSF),interleukin-4(IL-4)and tumor necrosis factor-?(TNF-?)to mature DC.The mature DC and T cells were mixed,then cultured with interleukin-2(IL-2)and interleukin-7(IL-7)resulting in generation of cytotoxic T lymphocyte(CTL),whose lethal effects on cancer cells were determined by 51chromium(51Cr)release assay.3H incorporation method was employed to detect the influence of rAAV/CEA transfected DC in the proliferation of activated T cells.Results rAAV medicated CEA gene was transferred into DC precursor successfully and the expression was high.Over 90% DC precursors expressed CEA protein.The viral gene was integrated into the DC chromosome.rAAV/CEA transfected DC could induce specific CTL which could specifically recognize and kill CEA-positive colorectal cancer LoVo cell line,and showed restrictive activity of anti-MHC class I antigen,while it was not able to kill the CEA-negative cancer cells.Conclusion The present study confirms that rAAV/CEA transfected DC vaccine can induce anti-tumor activity in vitro.It paves the way for further study on CEA as a target antigen for gene therapy on colorectal cancer.