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Figure 19.34 Diagrammatic representation of the mechanism of action of a monoclonal antibody to a specific antigen on the surface of a neoplastic cell. The antibody is conjugated to and is carrying a bacterial toxin, ricin A (A). The entire complex is endocytosed into the cell, and on degradation of the peptide the toxin is released intracellularly where it inhibits protein synthesis. (Adapted from Winkler et al., 1997, with permission of the author and publisher.)

Figure 19.34 Diagrammatic representation of the mechanism of action of a monoclonal antibody to a specific antigen on the surface of a neoplastic cell. The antibody is conjugated to and is carrying a bacterial toxin, ricin A (A). The entire complex is endocytosed into the cell, and on degradation of the peptide the toxin is released intracellularly where it inhibits protein synthesis. (Adapted from Winkler et al., 1997, with permission of the author and publisher.)

tered together with TIL. A summary diagram of these two forms of cellular adoptive immunotherapy is seen in Figure 19.36.

Dendritic Cells for the Immunotherapy of Neoplasia

Methods for the expansion of dendritic cells and other antigen-presenting cells are not as effective as those for NK cells. However, it is possible to isolate such cells from both neoplasms and normal tissues and manipulate them in cell culture. In experimental systems, bone marrow-derived dendritic cells pulsed with synthetic peptides as epitopes presented on the surface of neo-plastic cells have been used to elicit protective and therapeutic immunity to neoplasms in mice (Mayordomo et al., 1995). Phagocytosis of apoptotic cells from neoplasms by antigen-presenting cells (Henry et al., 1999) and fusion of dendritic and neoplastic cells (Gong et al., 1997) have also been methods tried with some success in experimental animals. A unique protocol that may have direct application in the human is the immunization of bone marrow transplantation donors with tumor antigens and the use of the transplant as adoptive therapy against the established

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