DNA Based Vaccine Is More Efficient than Non Pathogenic Live Vaccine for the Prevention of HPV16 E7 Overexpressing Cancers

Introduction: Vaccinology provides promising approaches for the control of various infectious diseases. Among different strategies, DNA vaccines offer attractive research opportunities for development of vaccines for induction of antigen specific immunity owing to their stability, simplicity of delivery, safety and cost effectiveness. However, there is a need to increase their potency by the use of adjuvants such as glycoprotein 96 and electroporation delivery. On the other hand, the attenuated or non pathogenic live vectors have been used to deliver DNA into cells as efficient delivery tools in gene therapy. Recently, a non pathogenic protozoan, Leishmania tarentolae (L. tar), has attracted attention as an in situ protein delivery vehicle. Cervical cancer is the second largest cause of cancer deaths among women worldwide and human papillomaviruses (HPV) is reportedly a frequent cause of this type of cancer. Methods: In the current study, we compared the potential of live L. tar based and DNA based vaccines expressing HPV16 E7 linked to C terminal fragment of gp96 in a tumor mouse model. Results: We found that subcutaneous DNA injection with E7 CT (gp96), followed by electroporation, generate a significant E7 specific IFN γ immune response and in vivo protective effects compared to transgenic L. tar E7 CT (gp96) in challenge experiments with TC 1. Conclusion: It could be concluded that the DNA vaccine showed higher efficacy compared to the non pathogenic live parasite based vaccine in the tumor mice model.