Preclinical evaluation of autologous dendritic cells transfected with mRNA or loaded with apoptotic cells for immunotherapy of high-risk neuroblastoma.

Children with high-risk neuroblastoma (NB) have a poor clinical outcome. The purpose of the present study was to evaluate different strategies for immunotherapy of high-risk NB based on vaccination with antigen-loaded dendritic cells (DCs). DCs are professional antigen-presenting cells with the ability to induce antitumor T-cell responses. We have compared DCs either loaded with apoptotic tumor cells or transfected with mRNA from the NB cell line HTB11 SK-N-SH, for their capacity to induce T-cell responses in vitro. Monocyte-derived DCs from healthy donors were loaded with tumor-derived antigens in the form of apoptotic cells or mRNA, matured and used to prime autologous T cells in vitro. After 1 week, T-cell responses against antigen-loaded DCs were measured by ELISPOT assay. DCs loaded with apoptotic NB cells or transfected with NB-cell mRNA were both able to efficiently activate autologous T cells. Both T cells of the CD8+ and CD4+ subset were activated. T cells activated by NB mRNA transfected DCs extensively crossreacted with DCs loaded with apoptotic NB cells and vice versa. The results indicate that loading of DCs with apoptotic NB cells or transfection with tumor mRNA represent promising strategies for development of individualized cancer vaccines/cancer gene therapy in treatment of NB.