Chimeric Human Papillomavirus-16 Virus-like Particles Presenting HIV-1 P18I10 Peptide: Expression, Purification, Bio-Physical Properties and Immunogenicity in BALB/c Mice

Int J Mol Sci. 2023 Apr 29;24(9):8060. doi: 10.3390/ijms24098060.

Abstract

Human papillomavirus (HPV) vaccines based on HPV L1 virus-like particles (VLPs) are already licensed but not accessible worldwide. About 38.0 million people were living with HIV in 2020 and there is no HIV vaccine yet. Therefore, safe, effective, and affordable vaccines against both viruses are an urgent need. In this study, the HIV-1 P18I10 CTL peptide from the V3 loop of HIV-1 gp120 glycoprotein was inserted into the HPV16 L1 protein to construct chimeric HPV:HIV (L1:P18I10) VLPs. Instead of the traditional baculovirus expression vector/insect cell (BEVS/IC) system, we established an alternative mammalian 293F cell-based expression system using cost-effective polyethylenimine-mediated transfection for L1:P18I10 protein production. Compared with conventional ultracentrifugation, we optimized a novel chromatographic purification method which could significantly increase L1:P18I10 VLP recovery (~56%). Chimeric L1:P18I10 VLPs purified from both methods were capable of self-assembling to integral particles and shared similar biophysical and morphological properties. After BALB/c mice immunization with 293F cell-derived and chromatography-purified L1:P18I10 VLPs, almost the same titer of anti-L1 IgG (p = 0.6409) was observed as Gardasil anti-HPV vaccine-immunized mice. Significant titers of anti-P18I10 binding antibodies (p < 0.01%) and P18I10-specific IFN-γ secreting splenocytes (p = 0.0002) were detected in L1:P18I10 VLP-immunized mice in comparison with licensed Gardasil-9 HPV vaccine. Furthermore, we demonstrated that insertion of HIV-1 P18I10 peptide into HPV16 L1 capsid protein did not affect the induction in anti-L1 antibodies. All in all, we expected that the mammalian cell expression system and chromatographic purification methods could be time-saving, cost-effective, scalable platforms to engineer bivalent VLP-based vaccines against HPV and HIV-1.

Keywords: BEVS/IC system; HIV-1; HPV16; cesium chloride gradients; chromatography; immunogenicity; mammalian 293F cell expression system; sucrose cushion; vaccines; virus-like particle.

MeSH terms

  • Animals
  • Antibodies, Viral
  • Capsid Proteins / chemistry
  • HIV-1*
  • Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18
  • Human Papillomavirus Viruses
  • Human papillomavirus 16 / genetics
  • Humans
  • Mammals
  • Mice
  • Mice, Inbred BALB C
  • Oncogene Proteins, Viral*
  • Papillomavirus Infections*
  • Peptides

Substances

  • Antibodies, Viral
  • Human Papillomavirus Recombinant Vaccine Quadrivalent, Types 6, 11, 16, 18
  • Peptides
  • Capsid Proteins
  • Oncogene Proteins, Viral

Grants and funding

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 681137. In addition, we acknowledge support by Instituto de Salud Carlos III_Proyectos de Investigación en Salud (AES2020_ PI20/00217), Direcció General de Recerca i Innovació en Salut (DGRIS), Catalan Health Ministry Generalitat de Catalunya, and Centro para el Desarrollo Tecnológico Industrial (CDTI) from the Spanish Ministry of Economy and Business, grant number IDI-20200297.