[Development of a lung cancer vaccine by transfecting dendritic cells with rAAV/CEA]

To study the feasibility of preparing a therapeutic lung cancer vaccine by transfecting dendritic cells (DCs) with adeno-associated virus vector carrying carcino-embryonic antigen gene (rAAV/CEA).

Adherent cells (monocytes) isolated from the peripheral blood of a healthy donor were infected with rAAV/CEA virus stock or pulsed with CEA peptide (control). The monocytes in both groups were induced into mature DCs with recombinant human GM-CSF, IL-4 and TNF-α. At day 7 of induction, the mature DCs were harvested and mixed with T lymphocytes. T cell proliferation stimulated by the DCs was assessed with (3)H-thymidine uptake, and the expression of IL-4, IFN-γ, CD8, CD4, CD25 and CD69 in cytotoxic T lymphocytes (CTL) was analyzed with flow cytometry. The cytotoxicity of the CTL against the target CEA-positive lung cancer A549 cells was tested by (51)Cr releasing assay.

The DCs transfected with rAAV/CEA strongly stimulated the proliferation of the T cell populations, and the induced CTL showed high expressions of CD8, CD69 and IFN-γ. The transfected DCs exhibited a high killing ability of CEA-positive lung cancer cells, and the killing showed a CEA antigen specificity and was limited by MHC I. These results suggested the ability of rAAV/CEA-transfected DCs in generating specific cellular immunity in vitro.

It is feasible to prepare therapeutic lung cancer vaccines by transfecting DCs with rAAV/CEA.