[Tumor RNA introduction into dendritic cells and Epstein-Barr virus transformed B cells]

In induction of autologous tumor-reactive antigen (TRA) specific cytotoxic T lymphocytes (CTLs) using antigenic peptides and cultured dendritic cells (DCs), identification of the adequate tumor antigens and HLA typing of individuals are required. These restrictions have promoted the use of tumor cells themselves, including tumor cell lysates and tumor cell-DC fusion cells. However, it is very difficult to obtain enough tumor cells for treatment in the clinical setting. We have studied the use of RNA derived from tiny tumor cells. RNA was reverse-transcribed into cDNA, after which T7-amplification and in vitro transcription were carried out. The amplified RNA was successfully electroporated into DCs, and polyclonal polyspecific CTLs could be generated. EBV transformed B cells were also good candidates to be electroporated with the RNA. This suggests that tumor RNA amplification followed by introduction into DCs or EBV transformed B cells is a feasible and practical method to prepare potent APCs.