Combined prophylactic and therapeutic immune responses against human papillomaviruses induced by a thioredoxin-based L2-E7 nanoparticle vaccine

PLoS Pathog. 2020 Sep 4;16(9):e1008827. doi: 10.1371/journal.ppat.1008827. eCollection 2020 Sep.

Abstract

Global burden of cervical cancer, the most common cause of mortality caused by human papillomavirus (HPV), is expected to increase during the next decade, mainly because current alternatives for HPV vaccination and cervical cancer screening programs are costly to be established in low-and-middle income countries. Recently, we described the development of the broadly protective, thermostable vaccine antigen Trx-8mer-OVX313 based on the insertion of eight different minor capsid protein L2 neutralization epitopes into a thioredoxin scaffold from the hyperthermophilic archaeon Pyrococcus furiosus and conversion of the resulting antigen into a nanoparticle format (median radius ~9 nm) upon fusion with the heptamerizing OVX313 module. Here we evaluated whether the engineered thioredoxin scaffold, in addition to humoral immune responses, can induce CD8+ T-cell responses upon incorporation of MHC-I-restricted epitopes. By systematically examining the contribution of individual antigen modules, we demonstrated that B-cell and T-cell epitopes can be combined into a single antigen construct without compromising either immunogenicity. While CD8+ T-cell epitopes had no influence on B-cell responses, the L2 polytope (8mer) and OVX313-mediated heptamerization of the final antigen significantly increased CD8+ T-cell responses. In a proof-of-concept experiment, we found that vaccinated mice remained tumor-free even after two consecutive tumor challenges, while unvaccinated mice developed tumors. A cost-effective, broadly protective vaccine with both prophylactic and therapeutic properties represents a promising option to overcome the challenges associated with prevention and treatment of HPV-caused diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Neoplasm* / chemistry
  • Antigens, Neoplasm* / pharmacology
  • Antigens, Viral* / chemistry
  • Antigens, Viral* / pharmacology
  • Archaeal Proteins* / chemistry
  • Archaeal Proteins* / pharmacology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / pathology
  • Cancer Vaccines* / chemistry
  • Cancer Vaccines* / pharmacology
  • Epitopes, B-Lymphocyte / chemistry
  • Epitopes, B-Lymphocyte / pharmacology
  • Epitopes, T-Lymphocyte / chemistry
  • Epitopes, T-Lymphocyte / pharmacology
  • Female
  • Humans
  • Immunity, Cellular / drug effects*
  • Mice
  • Mice, Inbred BALB C
  • Nanoparticles* / chemistry
  • Nanoparticles* / therapeutic use
  • Papillomaviridae* / chemistry
  • Papillomaviridae* / immunology
  • Papillomavirus Vaccines* / chemistry
  • Papillomavirus Vaccines* / pharmacology
  • Pyrococcus furiosus / chemistry*
  • Thioredoxins* / chemistry
  • Thioredoxins* / pharmacology
  • Uterine Cervical Neoplasms / immunology*
  • Uterine Cervical Neoplasms / virology

Substances

  • Antigens, Neoplasm
  • Antigens, Viral
  • Archaeal Proteins
  • Cancer Vaccines
  • Epitopes, B-Lymphocyte
  • Epitopes, T-Lymphocyte
  • Papillomavirus Vaccines
  • Thioredoxins

Grants and funding

This work was supported by the Wilhelm-Sander-Stiftung (2013.136.3) to X.Z., a stipend from the Chinese Scholarship Council (CSC) (201508080054) to X.Z. and by the Interuniversity Consortium for Biotechnology (CIB) (01_2018) to S.O. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.