Gene Transfer for Generation of Tumor and Leukemia Vaccines

Tumor vaccine strategies aim to compensate for the reduced immunogenicity of tumor cells (1 -4 ). Neoplastic cells fail to induce an effective antineoplastic immune response for a number of reasons, such as defective antigen-processing mechanisms, decreased levels of MHC expression, or lack of costimulatory molecules. In tumor vaccine generation, these deficits may be overcome either by introducing genes encoding for immunomodulatory molecules into the tumor vaccine cells or by employing professional antigen-presenting cells such as dendritic cells (DCs) that have been primed with tumor antigens. For preparation of tumor vaccine cells, choices have to be made with regard to autologous versus allogeneic target cells, the immunomodulatory genes used for transduction, and the appropriate gene transfer system used for the introduction of immunomodulatory molecules.