Engineering of highly immunogenic long-lived DC vaccines by antiapoptotic protein gene transfer to enhance cancer vaccine potency.

Dendritic cells (DCs) have a critical role in the induction of antigen-specific immune responses, transporting antigens from peripheral tissue to regional lymph nodes where they interact with antigen-specific T lymphocytes. Recent studies revealed that the efficacy of the T cell-dependent immune response depends on the lifespan of the antigen-presenting DCs in the lymph nodes. Here, we succeeded in engineering long-lived antigen-presenting DCs via Bcl-XL-derived hyperactive mutant antiapoptotic protein (Bcl-X FNK) gene transfer. In a B16BL6 melanoma model, these long-lived DCs exerted potent antitumor immunity that depended mainly on antigen-specific cytotoxic T lymphocytes. Furthermore, in vivo longevity of the long-lived DC vaccine led to antigen-specific activation of interferon-gamma-producing CD4+ and CD8+ T cells. Thus, the long-lived DC vaccine strategy is highly useful for constructing DC vaccines, as well as other cell-based medicines, such as stem cell therapy.