Intraduodenal Delivery of Exosome-Loaded SARS-CoV-2 RBD mRNA Induces a Neutralizing Antibody Response in Mice

Vaccines (Basel). 2023 Mar 16;11(3):673. doi: 10.3390/vaccines11030673.

Abstract

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has presented numerous challenges to global health. Vaccines, including lipid-based nanoparticle mRNA, inactivated virus, and recombined protein, have been used to prevent SARS-CoV-2 infections in clinics and have been immensely helpful in controlling the pandemic. Here, we present and assess an oral mRNA vaccine based on bovine-milk-derived exosomes (milk-exos), which encodes the SARS-CoV-2 receptor-binding domain (RBD) as an immunogen. The results indicate that RBD mRNA delivered by milk-derived exosomes can produce secreted RBD peptides in 293 cells in vitro and stimulates neutralizing antibodies against RBD in mice. These results indicate that SARS-CoV-2 RBD mRNA vaccine loading with bovine-milk-derived exosomes is an easy, cheap, and novel way to introduce immunity against SARS-CoV-2 in vivo. Additionally, it also can work as a new oral delivery system for mRNA.

Keywords: SARS-CoV-2; bovine-milk-derived exosomes; mRNA; neutralizing antibodies; oral vaccines; receptor-binding domain.

Grants and funding

This research was funded by Tingo Exosomes Technology Co., Ltd., Tianjin, China.