Using cryo-electron microscopy, the researchers showed that the Spike (S) protein in cells exposed to the AstraZeneca vaccine was very similar to the SARS-CoV-2 C protein.
New research has for the first time compared images of the Spike (S) protein that develops on the surface of cells exposed to the Oxford-AstraZeneca vaccine with the S protein SARS-CoV-2. The images show that S proteins are very similar to viral proteins and support the modified adenovirus used in the vaccine as a leading platform to combat COVID-19.
The study was conducted at the University of Southampton and the University of Oxford, both in the UK. According to the researchers, the SARS-CoV-2 virus uses S proteins that protrude from its surface to bind to and enter cells in the human body. These proteins are coated with sugars, known as glycans, that cover portions of viral proteins in the human immune system.
The vaccine, developed by the University of Oxford and AstraZeneca, is a vaccine with an adenoviral vector, which takes a safe version of the virus and adds information from part of the pathogen, in this case the SAR-CoV-2 S protein, to generate neutralizing antibodies against that target.
In a new study, scientists characterized SARS-CoV-2 proteins produced in cells represented by the Oxford-AstraZeneca vaccine. They were exposed through cells in vitro Oxford-AstraZeneca vaccine. Using cryo-electron microscopy (cryoEM), they made thousands of images which they then combined to create a clear image of the resulting S protein on the cells.
Professor Peijun Zhang of Oxford University, who led the imaging work, said: “CryoEM is an immensely powerful technique that has allowed us to visualize a dense array of piles produced and presented on the cell surface.”
Further chemical analysis of the glycans that overlay the newly developed S protein revealed that they have great similarity to those surrounding the SARS-CoV-2 S protein. According to the team, this is an essential feature of the vaccine because it means that it can provide close imitations of the coronavirus that are important for triggering the immune response needed to protect against COVID-19.
“In this study, we set a goal to see how close proteins induced by S proteins resemble infectious virus proteins. We were really pleased to see a large amount of N-like S protein, ”said Professor Max Crispin, who led the work in Southampton.
The findings were published in ACS Central Science.