ENHANCED ANTITUMOR EFFECTS OF TUMOR ANTIGEN-PULSED DENDRITIC CELLS BYTHEIR TRANSFECTION WITH GM-CSF GENE

To investigate the biological characterization and antitumor activitie s of GM-CSF gene-transfected dendritic cells, thr splenic dendritic ce lls were infected with GM-CSF recombinant replication-deficient adenov iruses in vitro. Their enhanced expression of B7 was demonstrated by F ACS analysis, and more potent stimulatory activity was confirmed by al logeneic MLR. Immunization of dendritic cells pulsed with irradiated B 16 melanoma cells induced significant CTL and enabled host to resist t he challenge of wild-type B16 cells. When they were transfected with G M-CSF gene subsequently, the induced CTL activity was higher, and the produced protection against B16 cell challenge and therapeutic effect on the mice with preestablished pulmonary metastases more effective. T hese data suggest that the dendritic cells pulsed with tumor antigen t hen transfected with GM-CSF gene can be used as an effective vaccine i n tumor immunotherapy.