Human papillomavirus type 16 E7 peptide 38–61 linked with an immunoglobulin G fragment provides protective immunity in mice

Abstract

Objective To explore whether the recombinant protein (Human papillomavirus (HPV) type16 E7 peptide 38–61 linked with an immunoglobulin G fragment) will generate protective immunity in mouse model. Methods In our study, we combined the HPV16 E7 peptide 38–61 with a murine IgG heavy chain constant region to construct a chimeric protein compound, which was highly expressed as inclusion bodies in a bacterial expression system with Escherichia coli. The purified chimeric protein was injected into C57BL/6 mice and the efficiency of the chimeric vaccine candidate was evaluated by antibody response assay, T cell proliferation assay, CTL assay, tumor challenge assay and therapeutic experiment. Results The chimeric vaccine candidate was able to induce anti-HPV antibodies as well as to elicit HPV16 E7-specific CTLs and T cell proliferation in a pre-clinical mouse model. It was also able to effectively protect mice against the challenge of HPV16-positive tumor cells, and to eradicate HPV16-expressing tumors in mice. Conclusions The chimeric protein vaccine can induce E7-specific immune responses and protect mice against challenge of HPV16-positive tumor, even eradicate developed tumor. The results indicated a possibility to use the chimeric protein vaccine to protect human against HPV infection.