A mRNA Vaccine Encoding for a RBD 60-mer Nanoparticle Elicits Neutralizing Antibodies and Protective Immunity Against the SARS-CoV-2 Delta Variant in Transgenic K18-hACE2 Mice

Front Immunol. 2022 Jul 6;13:912898. doi: 10.3389/fimmu.2022.912898. eCollection 2022.


Two years into the COVID-19 pandemic there is still a need for vaccines to effectively control the spread of novel SARS-CoV-2 variants and associated cases of severe disease. Here we report a messenger RNA vaccine directly encoding for a nanoparticle displaying 60 receptor binding domains (RBDs) of SARS-CoV-2 that acts as a highly effective antigen. A construct encoding the RBD of the Delta variant elicits robust neutralizing antibody response, and also provides protective immunity against the Delta variant in a widely used transgenic mouse model. We ultimately find that the proposed mRNA RBD nanoparticle-based vaccine provides a flexible platform for rapid development and will likely be of great value in combatting current and future SARS-CoV-2 variants of concern.

Keywords: K18-hACE2; SARS-CoV-2; delta variant; mRNA vaccine; nanoparticle; neutralizing antibody; receptor-binding domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19* / prevention & control
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Mice, Transgenic
  • Nanoparticles* / chemistry
  • Pandemics
  • SARS-CoV-2 / genetics
  • Spike Glycoprotein, Coronavirus
  • mRNA Vaccines* / immunology


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Spike Glycoprotein, Coronavirus
  • mRNA Vaccines
  • spike protein, SARS-CoV-2

Supplementary concepts

  • SARS-CoV-2 variants