Oxford/AstraZeneca vaccine turns cells into ‘little factories’ to fight off COVID-19

Scientists made the discovery after examining thousands of microscopic images to compare spike proteins on the SARS-CoV-2 virus.

Published: April 7, 2021 at 2:30 pm

Microscopic images have shown how the Oxford/AstraZeneca vaccine turns cells into “little factories” to fight off COVID-19.

Scientists from the University of Oxford and the University of Southampton have examined thousands of images to compare how the spike proteins from the coronavirus vaccine develop on the surface of cells.

The SARS-CoV-2 virus, which causes COVID-19, has a large number of spikes sticking out of its surface that it uses to attach to, and enter, cells in the human body.

These spikes are coated in sugars, known as glycans, which disguise parts of the viral proteins to the human immune system.

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The vaccine developed by the University of Oxford and AstraZeneca is an adenovirus-vectored vaccine, which means it involves taking a safe version of a virus and adding in the information from part of a pathogen, in this case the SARS-CoV-2 spike, in order to generate neutralising antibodies against that target.

The images taken for the study, published in the journal ACS Central Science, show that the spikes are “highly similar” to those of the virus and the researchers say this supports the modified adenovirus used in the vaccine as a leading method to combat COVID-19.

“In this study we set out to see how closely the vaccine induced spikes resembled those of the infectious virus. We were really pleased to see a large amount of native-like spikes,” said Prof Max Crispin, from the University of Southampton

“This study will hopefully provide further understanding for the public, helping them see how the Oxford/AstraZeneca vaccine works.

“Many people may not realise how their cells become little factories manufacturing viral spikes that then trigger the immune response needed to fight off the disease.

“This may also provide reassurance that the vaccine is doing its job and generating the material that we need to present to our immune systems.”

Reader Q&A: Why don't viruses like the flu die off when no one is ill?

Asked by: Andrew Cirel, via email

Strictly speaking, viruses can’t ‘die off’ as they’re just inanimate strips of genetic material plus other molecules. But the reason that they keep coming back is because they’re always infecting someone somewhere; it’s just that at certain times of the year, they’re less able to infect enough people to trigger a full-blown epidemic.

Many viruses flare up during the winter because people spend more time indoors in poorly-ventilated spaces, breathing in virus-laden air and touching contaminated surfaces. The shorter days also lead to lower levels of vitamin D, and this weakens our disease-fighting immune system. Experiments also suggest that the flu virus in particular remains infectious for longer in low temperatures.

But even when conditions aren’t ideal, viruses will find enough people to infect to ensure their survival, until they can come roaring back in an epidemic.

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