Tumor-derived Factors Responsible for Dendritic Cell dysfunction

Perpetuation of immune deficiency throughout tumor development is, to a great degree, the result of impairment of dendritic cell function by products secreted by tumors. They include cytokines, non-tumor-specific molecules (gangliosides, prostanoids, nitric oxide, etc.) and tumor-(specific) antigens (MUC-1, PSA, Her-2 neu). They may engender a distortion of dendritic cell development, block dendritic cell maturation, induce dendritic cell apoptosis or interfere with antigen presentation. Identifying those molecules and their interaction with dendritic cells will accelerate the development ofmore efficient immunotherapies. In this chapter we review the current literature on these interactions and highlight the possible avenues of minimization of their deleterious effects.