The COVID-19 pandemic sparked the need to develop an efficient and cost-effective vaccine to provide mass immunization against SARS-CoV-2, the virus that causes COVID-19. An Israeli study, initially published in June 2020 on the preprint server bioRxiv, examined the possibility of generating a new recombinant vaccine to protect against SARS-CoV-2. The report is now available on Nature Communications, proving a single-dose vaccine to be highly protective in an animal model.
Delta-G-VSV Pseudotyping System
The new study describes a VSV-∆G-spike vaccine, in which the VSV glycoprotein has been replaced by the SARS-CoV-2 spike protein. VSV is a single-stranded RNA virus that mostly affects animals rather than humans. The glycoprotein (G protein) is responsible for the attachment and entry of viruses into a susceptible host cell. By replacing the G protein of VSV with the spike protein of SARS-CoV-2, VSV pseudotypes are produced that greatly reduce the virulence of the SARS-CoV-2, making the viral propagation process easier and safer for experimentation.
The study uses VSV plasmid expression vectors from our Delta-G-VSV Pseudotyping System, developed by Michael A. Whitt from the University of Tennessee. The system is used as a model for identifying cellular receptors for viruses, screening for entry inhibitors, and evaluating neutralizing antibody responses following vaccination. It has been used to study viruses that typically require high-level containment – such as Ebola or HIV – at just biosafety level 2 (BSL-2) containment.
Most recently, the Delta-G-VSV Pseudotyping System has been applied to COVID-19 research and vaccine development. We were particularly excited that the system’s reagents were used in the development of the BioNTech-Pfizer vaccine; learn more here.
Hamster Model of Successful Vaccine
In the new Nature Communications paper, the researchers used the golden Syrian hamster model to evaluate their rVSV-ΔG spike vaccine. COVID-19 infected animals present features such as weight loss and changes in the lung tissue.
Using a single dose of the vaccine, the researchers incrementally increased the dosage to find the right level while noting for adverse effects. Their results show no animals presented post-immunization weight loss or other signs of illness, while proving the vaccination results in a rapid and powerful emergence of SARS-CoV-2 neutralizing antibodies. This indicates the discovery of a protective, safe, and effective vaccine in a single dose.
Are you interested in this field of research? Check out more of our COVID-19 and SARS-CoV-2 research reagents; view our full list here! See below for more: