Pre-clinical development of chimeric virus-like particles based HPV: HIV vaccines by using mammalian cell expression system: limitations and challenges

Abstract

[eng] HPV and HIV-1 are important public health issues in some developing and industrialized countries, but an effective chimeric HPV:HIV preventive vaccine is still unachievable. We aimed to establish an alternative mammalian (293F) cell expression system combining with chromatographic purification methods to reach an appreciable expression level, purity and recovery rate of chimeric HPV:HIV VLPs. In this study, the chimeric HPV:HIV (L1:P18I10 and L1:T20) immunogens were designed and produced by using 293F expression system. The HPV:HIV VLPs were subsequently purified by a 3-step chromatographic method, including cation (CEC), size exclusion (SEC) and heparin affinity (H-AC) chromatography. Then, the in vitro stability, in vitro self assembly and morphology of purified HPV:HIV VLPs were confirmed by non-reducing SDS-PAGE, molecular mass assay, transmission electron microscopy (TEM) respectively. The sequential and conformational P18I10 and T20 peptides presented on chimeric HPV:HIV VLPs were further characterized by HIV-1 anti-V3 and anti-2F5 monoclonal antibodies in vitro by using Western blot and indirect ELISA. Finally, the immunogenicity of HPV:HIV VLPs were assessed in BALB/c mice model. Because the development and manufacturing of an immunogenic HPV:HIV vaccine is still unachievable, this study provided a baseline strategy that may be worthy to support the global efforts to develop novel chimeric VLP-based vaccines for controlling HPV and HIV-1 infections