Mutants of plant genes for developing cancer vaccines

Preventive Human Papillomavirus (HPV) vaccination is an expensive practice and it may be an insufficient tool to tackle cervical cancer worldwide. Therapeutic intervention is seeking for safe/effective vaccines inducing the activation of CD8+ cytotoxic T lymphocytes (CTLs) that is required to clear the tumor. Linking a tumor-specific antigen (i.e. the E7 oncoprotein of the ‘high risk’ HPVs) to molecules able to increase its immune ‘visibility’ represents a strategy to force the immune system to fight cancer. We focused on plants as sources of innovative immunostimulatory sequences. We have already shown the anti-cancer activity obtained by fusing E7GGG (a mutagenized E7 gene from the high risk HPV type 16) to the coat protein of a plant virus, the Potato Virus X. We are now investigating plant-derived carriers, such as the ‘Ribosome inactivating proteins’ (RIPs), so far used to develop immunotoxins for targeted cancer therapy. Beside toxicity, RIPs have other features (i.e. immunogenicity, ability to modu...