Protein vaccination with HPV16 E7/Pep‐1 nanoparticles elicits a protective T‐helper cell‐mediated immune response

Two human papillomavirus (HPV) viral oncoproteins, E6 and E7 represent ideal targets for development of a therapeutic HPV vaccine. It is important to reduce the rate of HPV‐associated malignancies through improvement of vaccine modalities. In this study, we used a short amphipathic peptide carrier, Pep‐1, for delivery of the full‐length HPV16 E7 protein into mammalian cells and evaluated immune responses and protective effects of different formulations in C57BL/6 tumor mice model. Our results showed that the complexes of E7/Pep‐1 protein form stable nanoparticles through noncovalent binding with an average size of 120 to 250 nm. The efficient delivery of E7 protein by Pep‐1 at molar ratio of 1:20 was detected in HEK‐293T cell line for 1 h and 3 h post‐transfection. Immunization with E7/Pep‐1 nanoparticles at a ratio of 1:20 induced a higher Th1 cellular immune response with the predominant IgG2a and IFN‐γ levels than those induced by E7 protein in a murine tumor model. These data suggest that Pep‐1 peptide would indicate promising applications for improvement of HPV therapeutic vaccines. © 2016 IUBMB Life, 68(6):459–467, 2016