GENE-MODIFIED TUMOR-CELLS AS CELLULAR VACCINE

The identification and characterization of many tumor antigens and the parallel explosion of knowledge of the cellular and molecular mechani sms of antigen recognition by the immune system have given renewed hop es that immunogenetherapy could be a promising modality to treat certa in tumors. Many different novel strategies have been developed to deri ve genetically modified tumor cells and use them as cellular vaccines to induce useful antitumor immunity in a variety of animal tumor model s. This review discusses induction of tumor immunity by injecting tumo r cells that are genetically engineered to secrete various cytokines a nd to express major histocompatibility complex molecules and/or costim ulatory molecules. While there has been a great success in inducing ex cellent antitumor immunity in a variety of tumor models, there are som e difficulties and limitations in the application of these gene-modifi ed tumor cells for the treatment of preexisting tumors. A number of im provements and modifications are already underway to overcome some of these problems.