A non-pathogenic live vector as an efficient delivery system in vaccine design for the prevention of HPV16 E7-overexpressing cancers.

The attenuated or non-pathogenic live vectors have been evolved specifically to deliver DNA into cells as efficient delivery tools in gene therapy. Recently, a non-pathogenic protozoan, Leishmania tarentolae (L.tar) has attracted a great attention. In current study, we used Leishmania expression system (LEXSY) for stable expression of HPV16 E7 linked to different mini-chaperones [N-/C-terminal of gp96] and compared their immunogenicity and protective effects in C57BL/6 mice against TC-1 challenge. TC-1 murine model is primary C57BL/6 mice lung epithelial cells co-transformed with HPV16 E6, HPV16 E7 and ras oncogenes. Our results showed that subcutaneous administration of mice with both the recombinant L.tar-E7-NT (gp96) and L.tar-E7-CT (gp96) led to enhance the levels of IFN-γ and also IgG2a before and after challenge with TC-1. Furthermore, L.tar-E7-CT (gp96) live vaccine indicated significant protective effects as compared to control groups as well as group vaccinated with L.tar-E7. Indeed, the recombinant live vector is capable of eliciting effective humoral and cellular immune responses in mice, but however, further studies are required to increase their efficacy.