HPV16 E5 peptide vaccine in treatment of cervical cancer in vitro and in vivo

Summary Human papillomavirus (HPV)-induced cervical cancer is the second most common cancer among women worldwide. Despite the encouraging development of the preventive vaccine for HPV, a vaccine for both prevention and therapy or pre-cancerous lesions remains in high priority. Thus far, most of the HPV therapeutic vaccines are focused on HPV E6 and E7 oncogene. However these vaccines could not completely eradicate the lesions. Recently, HPV E5, which is considered as an oncogene, is getting more and more attention. In this study, we predicted the epitopes of HPV16 E5 by bioinformatics as candidate peptide, then, evaluated the efficacy and chose an effective one to do the further test. To evaluate the effect of vaccine, rTC-1 (TC-1 cells infected by rAAV-HPV16E5) served as cell tumor model and rTC-1 loading mice as an ectopic tumor model. We prepared vaccine by muscle injection. The vaccine effects were determined by evaluating the function of tumor-specific T cells by cell proliferation assay and ELISPOT, calculating the tumor volume in mice and estimating the survival time of mice. Our in vitro and in vivo studies revealed that injection of E5 peptide+CpG resulted in strong cell-mediated immunity (CMI) and protected mice from tumor growth, meanwhile, prolonged the survival time after tumor cell loading. This study provides new insights into HPV16 E5 as a possible target on the therapeutic strategies about cervical cancer.