Recombinant vaccinia virus expressing cytokine GM-CSF as tumor vaccine

The efficacy of a recombinant vaccinia virus (rvv-GM-CSF) expressing the granulocyte macrophage colony stimulating factor (GM-CSF) as tumor vaccine was evaluated in the murine B16-F10 melanoma model. The vaccine was prepared by infection of irradiated tumor cells with rvv-GM-CSF. Control vaccine was B-16 cells infected with a recombinant vaccinia virus expressing Escherichia coli beta-galactosidase (rvv-lacZ). Pre-vaccination of naive C57BL/6 mice later inoculated with tumor cells and treatment of mice bearing tumors with GM-CSF vaccine inhibited tumor development and prolonged survival. Lung metastasis of B-16 was also inhibited by treatment with GM-CSF vaccine. The vaccine effects appeared to be tumor cell specific. The efficacy of the vaccine was comparable to a retroviral vaccine (MFG-muGM-CSF) in this system. The vaccine was also effective when rvv-GM-CSF was directly injected into the tumor. These data suggest that this vaccine approach has potential for use in cancer treatment, especially for patients with easily accessible tumors.