Immunogenicity and therapeutic efficacy of dendritic-tumor hybrid cells generated by electrofusion

Dendritic cells (DCs) are potent antigen-presenting cells capable of inducing strong immune responses to weak tumor-associated antigens. Among various DC-based approaches, cancer immunotherapy with DC-tumor fusion hybrids offers advantages of polyclonal stimulation of a diverse array of tumor antigens. However, prevalent fusion methods using chemical fusogens such as polyethylene glycol often result in toxicity and low fusion efficiency. In this article, we describe an electro-fusion technique, applicable to processing large numbers of cells with consistent and high fusion efficiency. Generation of fusion hybrids was verified by unequivocal experimental evidence. In animal models, fusion hybrids expressed the mature DC-like phenotype. They stimulated both CD4 and CD8 tumor-specific T cells to secrete interferon-γ in vitro. In immunotherapy, a single vaccination with DC-tumor fusion cells along with interleukin-12 as an adjuvant eradicated tumors established in the skin and lung. These results provide an impetus for treating cancer patients with similarly generated cells.