Dendritic cells (DCs) are mediators between innate and adaptive immunity and can initiate or moderate antigen-specific immune responses based on their phenotypic profile i.e., whether they are activating or tolerogenic. They exert their effects by presenting antigens on their surfaces to other cells of the immune system. The fact that DCs with a tolerogenic phenotype can be generated in vitro, offers the opportunity to feed those cells with specific antigens known to be involved in various immunological disease processes. Adoptive transfer of antigen-fed tolerogenic DCs can then specifically prevent or interfere with diseases caused by such undesirable immune activation. By antigen-specific intervention rather than by general immunosuppression, the immune system maintains its capability to respond to infections and cancer.