Self-Assembling Nanoparticle Vaccines Displaying the Receptor Binding Domain of SARS-CoV-2 Elicit Robust Protective Immune Responses in Rhesus Monkeys

Bioconjug Chem. 2021 May 19;32(5):1034-1046. doi: 10.1021/acs.bioconjchem.1c00208. Epub 2021 May 5.

Abstract

SARS-CoV-2 caused the COVID-19 pandemic that lasted for more than a year. Globally, there is an urgent need to use safe and effective vaccines for immunization to achieve comprehensive protection against SARS-CoV-2 infection. Focusing on developing a rapid vaccine platform with significant immunogenicity as well as broad and high protection efficiency, we designed a SARS-CoV-2 spike protein receptor-binding domain (RBD) displayed on self-assembled ferritin nanoparticles. In a 293i cells eukaryotic expression system, this candidate vaccine was prepared and purified. After rhesus monkeys are immunized with 20 μg of RBD-ferritin nanoparticles three times, the vaccine can elicit specific humoral immunity and T cell immune response, and the neutralizing antibodies can cross-neutralize four SARS-CoV-2 strains from different sources. In the challenge protection test, after nasal infection with 2 × 105 CCID50 SARS-CoV-2 virus, compared with unimmunized control animals, virus replication in the vaccine-immunized rhesus monkeys was significantly inhibited, and respiratory pathology observations also showed only slight pathological damage. These analyses will benefit the immunization program of the RBD-ferritin nanoparticle vaccine in the clinical trial design and the platform construction to present a specific antigen domain in the self-assembling nanoparticle in a short time to harvest stable, safe, and effective vaccine candidates for new SARS-CoV-2 isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / immunology
  • Binding Sites
  • CD8-Positive T-Lymphocytes / immunology
  • COVID-19 / immunology
  • COVID-19 / prevention & control*
  • COVID-19 Vaccines / immunology*
  • Ferritins / chemistry
  • Ferritins / metabolism
  • Immunity, Humoral
  • Macaca mulatta
  • Male
  • Nanoparticles / chemistry*
  • Nanoparticles / metabolism
  • SARS-CoV-2 / isolation & purification
  • SARS-CoV-2 / physiology
  • Spike Glycoprotein, Coronavirus / genetics
  • Spike Glycoprotein, Coronavirus / immunology
  • Spike Glycoprotein, Coronavirus / metabolism*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • Ultracentrifugation

Substances

  • Antibodies, Neutralizing
  • COVID-19 Vaccines
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2
  • Ferritins