Vaccination therapy with tumor-dendritic cell hybrids: a promising therapeutic approach?

Dendritic cells (DCs) are potent antigen-presenting cells currently being investigated as a tool for antitumor vaccination strategies. As an alternative to loading DCs with tumor antigen preparations, hybrid cells generated by fusing tumor cells with DCs have successfully been evaluated in preclinical cancer models. Hybrid cells express a large repertoire of tumor-associated antigens, high levels of major histocompatibility complex class I and II molecules, and adhesion/co-stimulatory molecules. Therefore, these cells possess properties of both parental cell types that are necessary for the induction of primary helper and cytotoxic T-cell responses. The results of early clinical trials suggest that hybrid cell vaccination is a safe and well-tolerated procedure capable of inducing T-cell responses. However, the few objective clinical responses observed indicate that further optimizations are required.