Expression of HPV-16 L1 capsomeres with glutathione-S-transferase as a fusion protein in tobacco plastids: an approach for a capsomere-based HPV vaccine

Hum Vaccin Immunother. 2014;10(10):2975-82. doi: 10.4161/21645515.2014.970973. Epub 2014 Nov 19.

Abstract

Human Papillomavirus (HPV) is the main cause of cervical cancer, which is the second most severe cancer of women worldwide, particularly in developing countries. Although vaccines against HPV infection are commercially available, they are neither affordable nor accessible to women in low income countries e.g. Africa. Thus, alternative cost-effective vaccine production approaches need to be developed. This study uses tobacco plants to express pentameric capsomeres of HPV that have been reported to generate elevated immune responses against HPV. A modified HPV-16 L1 (L1_2xCysM) protein has been expressed as a fusion protein with glutathione-S-transferase (GST) in tobacco chloroplasts following biolistic transformation. In total 7 transplastomic lines with healthy phenotypes were generated. Site specific integration of the GST-L1_2xCysM and aadA genes was confirmed by PCR. Southern blot analysis verified homogenous transformation of all transplastomic lines. Antigen capture ELISA with the conformation-specific antibody Ritti01, showed protein expression as well as the retention of immunogenic epitopes of L1 protein. In their morphology, GST-L1 expressing tobacco plants were identical to wild type plants and yielded fertile flowers. Taken together, these data enrich knowledge for future development of cost-effective plant-made vaccines against HPV.

Keywords: ELISA, enzyme-linked immunosorbent assay; GST; GST, glutathione-s-transferase; HPV, human papillomavirus; HPV-16 L1; L1_2xCysM, modified L1 gene; PCR, polymerase chain reaction; Plant-made vaccines; VLPs, virus-like particles; aadA, aminoglycoside 3'-adenylyltransferase; capsomeres; cervical cancer; plastid transformation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Capsid Proteins / biosynthesis
  • Capsid Proteins / genetics
  • Capsid Proteins / immunology*
  • Epitopes / immunology
  • Female
  • Glutathione Transferase / biosynthesis
  • Glutathione Transferase / genetics
  • Human papillomavirus 16 / genetics
  • Human papillomavirus 16 / immunology*
  • Humans
  • Oncogene Proteins, Viral / biosynthesis
  • Oncogene Proteins, Viral / genetics
  • Oncogene Proteins, Viral / immunology*
  • Papillomavirus Infections / immunology
  • Papillomavirus Infections / prevention & control
  • Papillomavirus Vaccines / biosynthesis
  • Papillomavirus Vaccines / immunology*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Plastids / genetics
  • Plastids / metabolism
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology*
  • Tobacco / genetics*
  • Tobacco / metabolism

Substances

  • Capsid Proteins
  • Epitopes
  • Oncogene Proteins, Viral
  • Papillomavirus Vaccines
  • Recombinant Fusion Proteins
  • L1 protein, Human papillomavirus type 16
  • Glutathione Transferase