Novel Self-Amplifying RNA Lipid Nanoparticle Vaccines

The increase of the SARS-CoV-2 into a global pandemic within a few months of onset motivates developing a rapidly scalable vaccine.

In an article published in nature communication this year, the Department of Infectious Diseases, Imperial College London group (Paul F. McKay et al.), demonstrates vaccine formulation using a self-amplifying RNA encoding the SARS-CoV-2 spike protein encapsulated within a lipid nanoparticle (LNP).

In a set of experiments, they observed the too high generation of dose-dependent SARS-CoV-2 antibodies titers in mice samples, as well as substantial neutralization of both a wild-type virus and pseudo-virus.

With several types of characterizations, they showed that the neutralization is comparative to the number of IgG’s and of greater magnitude than recovered COVID-19 patients.

On the other hand, the saRNA-LNP immunizations stimulated a Th1 biased reaction in mice samples, and as a result, there were no antibody-dependent enhancement (ADE) observed.

Lastly, the team followed high cellular responses, as characterized by IFN-γ production, upon re-stimulation with SARS-CoV-2 peptides. The paper’s data and this impressive work give an insight into the vaccine development and validation of immunogenicity to enable rapid translation of vaccine research to the clinic.

References:

1. McKay, P.F., Hu, K., Blakney, A.K., Samnuan, K., Brown, J.C., Penn, R., Zhou, J., Bouton, C.R., Rogers, P., Polar, K. and Lin, P.J., 2020. self-amplifying RNA SARS-CoV-2 lipid nanoparticle vaccine candidate induces high neutralizing antibody titers in mice. Nature communications, 11(1), pp.1-7.