A number of strategies are under development by various groups for the creation of therapeutic tumor vaccines using gene transfer in autologous tumor cells. However, gene transfer entails a number of technical problems that limit both the clinical utility and commercial viability of such vaccines. As an alternative, this project will identify a chimeric GPI-linked molecule that improves the efficiency of events in the afferent limb of the immune response. The utility of this molecule in the creation of tumor vaccines will be tested in mouse models