Today, the human papillomavirus (HPV) L1 protein is the main target in the construction of prophylactic HPV vaccines. The production of virus-like particles (VLPs) that closely resemble the natural structure of the HPV16 virus and induce high levels of virus-neutralizing antibodies in animals and humans is facilitated by the expression of HPV16-L1 protein in eukaryotic cells. The Bac-to-Bac system has been previously used to produce high levels of recombinant proteins. In this study, we utilized this expression system to generate HPV16-L1 VLPs in (Sf9) insect cells. The wild-type L1 gene of papillomavirus type 16 was selected from Gene Bank and placed in bacmid structure after codon optimization using pFast Ba... More
Today, the human papillomavirus (HPV) L1 protein is the main target in the construction of prophylactic HPV vaccines. The production of virus-like particles (VLPs) that closely resemble the natural structure of the HPV16 virus and induce high levels of virus-neutralizing antibodies in animals and humans is facilitated by the expression of HPV16-L1 protein in eukaryotic cells. The Bac-to-Bac system has been previously used to produce high levels of recombinant proteins. In this study, we utilized this expression system to generate HPV16-L1 VLPs in (Sf9) insect cells. The wild-type L1 gene of papillomavirus type 16 was selected from Gene Bank and placed in bacmid structure after codon optimization using pFast Bac vector. The recombinant baculovirus containing HPV-16/L1 gene was then provided using the Bac-to-Bac system. It should be mentioned that the vector was transfected into the Sf9 cell. The cells were then lysed and the expression of L1 protein was revealed by SDS-PAGE and confirmed by Western Blot. The L1 purification was performed through Ni-NTA chromatography. The VLP formation of papillomavirus L1 protein was visualized by transmission electron microscopy. The expressed recombinant L1 was ~60 KD on SDS-PAGE which was identified in western blot by a specific anti-L1 monoclonal antibody. The electron microscopy confirmed the assembly of VLPs. Results of this study showed that the production of this protein at the industrial level can be optimized using a baculovirus/Sf9 system. The characteristics and advantages of this system are promising and it is a suitable candidate for protein synthesis.
