DENDRITIC CELLS FUSED WITH MASTOCYTOMA-CELLS ELICIT THERAPEUTIC ANTITUMOR IMMUNITY

Characterization of the spontaneous immune response that frequently oc curs in tumor-bearing animals, as well as immunization using dendritic cells pulsed with tumor antigens, suggests that a limiting factor of the tumor-specific immune response may be a defect in the co-stimulato ry signal that is required for optimal activation of T cells. In this work, we describe a new approach to improve the antigen-presenting cap acity of tumor cells, which does not require a source of purified tumo r-associated antigen. We fused P815 mastocytoma cells with bone marrow -derived dendritic cells. We obtained one hybrid that displayed the ph enotypic and functional properties of dendritic cells and expressed mR NA coding for the tumor-associated antigen P815 A/B. Injections of irr adiated hybrid cells prevented the growth of preimplanted mastocytoma and induced long-lasting tumor resistance. (C) 1998 Wiley-Liss, Inc.