[New technologies for immunotherapy against cancer: development of cell expansion technology and viruses as immune boosters].

Dendritic cells (DCs) play a crucial role in maintaining the immune system. Although DC-based cancer immunotherapy has been suggested as a potential treatment for various kinds of malignancies, clinical efficacies have been still unsatisfactory. To improve the clinical outcome of DC-based cancer immunotherapy, we are now focusing on 1) increase of numbers of therapeutic immune cells, i.e., DCs, and 2) the development of new methods for stimulating them. We have recently established a possible breakthrough, a simple cytokine-based culture method to realize a log-scale order of functional myeloid-type murine/human DCs. Moreover, we demonstrated that DCs activated by replication-deficient recombinant Sendai virus (rSeV) were highly effective than that seen in the use of current DC vaccine stimulated by conventional cytokines etc., for immunotherapy against malignancies. Therefore, our study strongly suggests that these improvements could overcome the current limitations of DC-based immunotherapy for malignancies.