Cancer immunotherapy with dendritic cells engineered to express tumor antigens

Dendritic cells engineered to express tumor-associated antigens can be used to prime and potentiate cytotoxic T cell responses against cancer cells. Numerous delivery systems for introducing genes to dendritic cells have been examined, which include (I) Viral vector systems such as Moloney leukemia virus vector (MLV), human immunodeficiency virus (HIV) vector, and adenovirus vector, vaccinia virus vector, canarypox virus vector and herpes simplex virus (HSV) vector, and (II) Non-viral vector systems such as cationic liposome, particle bombardment (gene gun) and electroporation methods. In this review, we adress several issues regarding these gene delivery systems in terms of genetic modification of dendritic cells. Since every method has advantages and/or disadvantages, the optimal methods for presenting antigen epitopes to dendritic cells need to be clarified. Several animal models by using dendritic cells transduced with model tumor antigens have shown in vivo antitumor effects, suggesting the potential clinical usefulness of this strategy.