Combined immunization with human papillomavirus type 18 fusion protein and recombinant vaccinia virus in mice

Abstract

Objective To investigate the cellular and humoral immune responses induced by combined immunization with the fusion protein of human papillomavirus type 18 (HPV18) and the recombinant vaccinia virus. Methods Purified HPV18L231-600E7E6 fusion protein, expressed by prokaryotic expression system, were immunized in combination with the recombinant vaccinia virus vaccine expressing HPV18E7E6 fusion protein (rVV18E7E6) by using various prime-boost regiments in C57BL/6 mice. Cellular and humoral immune responses were analyzed by enzyme-linked immunospot assay (ELISPOT), enzyme-linked immunosorbent assay (ELISA), and pseudovirus neutralization assay. Results Higher levels of cellular immune responses were induced in mice primed with the HPV18L231-600E7E6 fusion protein/adjuvant CpG and boosted with the recombinant vaccinia virus rVV18E7E6, than in other immunized mice. Higher binding antibody level was induced, and low level neutralizing antibody against pseudovirus was detected simultaneously. Conclusions Priming with HPV18L231-600E7E6 fusion protein/CpG and boosting with the recombinant vaccinia virus rVV18E7E6 could induce higher cellular and humoral immune response in immunized mice, which might be taken as vaccine candidate for treatment of HPV18 chronic infection and postoperative adjuvant treatment for cervical cancer. Key words: Human papillomavirus; Cervix neoplasms; Vaccine; Immunization therapy