Human Papillomavirus (HPV) E7 protein 49-57

Background: Therapeutic vaccines for cancer are an attractive alternative to conventional therapies, since the later result in serious adverse effects and in most cases are not effective against advanced disease. Human papillomavirus (HPV) is responsible for several malignancies such as cervical carcinoma. Vaccines targeting oncogenic viral proteins like HPV16-E6 and HPV16-E7 are ideal candidates to elicit strong immune responses without generating autoimmunity because: (1) these products are not expressed in normal cells and (2) their expression is required to maintain the malignant phenotype. Our group has developed peptide vaccination strategy called TriVax, which is effective in generating vast numbers of antigen-specific T cells in mice capable of persisting for long time periods. Materials and methods: We have used two HPV-induced mouse cancer models (TC-1 and C3.43) to evaluate the immunogenicity and therapeutic efficacy of TriVax prepared with the immunodominant CD8 T-cell epitope HPV16-E7(49-57), mixed with poly-IC adjuvant and costimulatory anti-CD40 antibodies. Results: TriVax using HPV16-E7(49-57) induced large and persistent T-cell responses that were therapeutically effective against established HPV16-E7 expressing tumors. In most cases, TriVax was successful in attaining complete rejections of 6-11-day established tumors. In addition, TriVax induced long-term immunological memory, which prevented tumor recurrences. The anti-tumor effects of TriVax were independent of NK and CD4 T cells and, surprisingly, did not rely to a great extent on type-I or type-II interferon. Conclusions: These findings indicate that the TriVax strategy is an appealing immunotherapeutic approach for the treatment of established viral-induced tumors. We believe that these studies may help to launch more effective and less invasive therapeutic vaccines for HPV-mediated malignancies.

Objectives: Human papillomavirus infection (HPV) is the most common viral infection which is causes of cervical, penal, vulvar, anal and, oropharyngeal cancer. E7 protein of HPV is a suitable target for induction of T cell responses and controlling HPV-related cancer. The aim of the current study was to designed and evaluated a novel fusion protein containing the different E7 proteins of the HPV 16, 18, 6 and 11, linked to the cell-penetrating peptide HIV-1 Tat 49-57, in order to improve cytotoxic immune responses in in-vitro and in-vivo. Results: In this study whole sequence of HPV16,18,6,11 E7-Tat (47-57) and HPV16,18,6,11 E7 cloned into the vector and expressed in E. coli (BL21). The purified protein was confirmed by SDS page and western blotting and then injected into the C57BL/6 mice. The efficiency of the fusion protein vaccine was assessed by antibody response assay, cytokine assay (IL-4 and IFN-γ), CD + 8 cytotoxicity assay and tumor challenge experiment. Result showed that fusion proteins containing Adjuvant (IFA,CFA) could express higher titer of antibody. Also, we showed that vaccination with E7-Tat and, E7-Tat-ADJ induced high frequencies of E7-specific CD8 + T cells and CD107a expression as well as IFN-γ level and enhanced long-term survival in the therapeutic animal models. Conclusion: Our finding suggested that this novel fusion protein vaccine was able to induce therapeutic efficacy and immunogenicity by improving CD8 + T cell in TC-1 tumor bearing mice; so this vaccine may be appreciated for research against HPV and tumor immunotherapies.

Several strategies have been used to enhance the vaccine-induced immunity of peptide vaccines and effective therapeutic benefits, including the utilization of heat shock proteins (HSP), especially the HSP70 family. HSP110 exhibits a higher binding affinity with protein and is capable of enhancing the immunogenicity of protein antigens; however, whether HSP110 can also increase the efficiency of peptide vaccine remains unclear. Here, we investigated mHSP110 as a chaperone immunoadjuvant to enhance the immune response to HPV16 oncoprotein E7-derived CTL epitope E7(49-57) in a mouse model. We developed the HSP110-E7(49-57) complex and demonstrated that mHSP110 could form complexes with peptide E7(49-57) using FITC-labeled E7(49-57) as the tracer. Inoculation of the mHSP110-E7(49-57) complex was capable of priming strong epitope-specific immune response as determined by its ability to elicit an epitope-specific splenocytes proliferation and a cytotoxic T cell response, and IFNgamma production in splenocytes. Results also showed that immunization with the mHSP110-E7(49-57) complex completely protected mice against subsequent challenge with tumor cells. More importantly, immunization of this complex also significantly inhibited the growth of established tumors and prolonged the survival time of the tumor-bearing animals. Thus, mHSP110-E7(49-57) complex vaccine represents a potentially powerful approach for use in the immunotherapy of cervical cancer associated with HPV16 infection. More importantly, the multi-epitopes derived from E7 and other E proteins can be applied to the strategy described in this study to form a multi-antigenic vaccine to induce an improved antitumor immune response to cervical cancer in the future.