CUTTING EDGE - PHYSICAL INTERACTION BETWEEN DENDRITIC CELLS AND TUMOR-CELLS RESULTS IN AN IMMUNOGEN THAT INDUCES PROTECTIVE AND THERAPEUTICTUMOR REJECTION

Dendritic cells (DCs) are potent professional APCs capable of presenti ng Ag in the context of costimulatory signals necessary for T cell act ivation. Although tumor cells express target Ags, they are generally i ncapable of stimulating an immune response. We show that the short ter m physical interaction of DCs and tumor cells, with or without cell fu sion, results in rapid, efficient, and stable DC-tumor cell associatio n. Immunization of naive mice with unselected, irradiated DC-tumor cel l conjugates induces tumor-specific CD8(+) cytotoxic T cells and prote ction from lethal tumor challenge. Furthermore, the immunogenicity of this cellular vaccine is dependent on the physical interaction of DCs and tumor cells before injection. Immunization with DCs and tumor cell s after physical interaction can result in the regression of establish ed tumors and persistent antitumor immunity. These results suggest tha t immunization with DC-tumor cell vaccines may be a simple, rapid, and potent strategy for tumor immunotherapy.