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why the alpha variant was a 'resounding success' for the covid virus
'we have never seen anything like this before,' said one of the authors of a new study on the alpha variant's evolution.
dec 31 2021
3 minute read
every cell in the nose, throat, and lungs, have sensors that can detect a virus — but covid can bypass them. (getty)
the original covid-19 virus — what is now often referred to as the alpha variant — evolved to evade our innate immune system, according to a new study.
every cell in the nose, throat, and lungs, have sensors that can detect a virus, and produce the interferon protein, which can alert our bodies to start an anti-viral response. antagonism proteins, such as the ones found in the covid-19 virus, can bypass those sensors.
the study, from the university of california san francisco, was published earlier this week in the scientific journal nature .
“we found that the sars-cov-2 alpha variant had adapted to avoid triggering our defensive frontline innate immune response much better than the first wave viruses,” co-first author lucy thorne said in a statement . “ we discovered it does this by making more of the virus proteins that can disable the innate immune system. these proteins are called n, orf6 and orf9b and are known as innate immune antagonists.”
by mutating the virus to evade our system, the alpha variant was able to replicate without our bodies knowing in the early stages of infection, thorne said. that ability to evade our detection is thought to give it a significantly higher risk to infect a person. she called it a “resounding success” for the virus, allowing it to then spread easier from person to person.
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to monitor the virus, researchers added samples of the alpha variant to artificially grown lung cells. they then watched for how the virus grew, looking to see whether an immune response was activated by the lung cells by checking the amount of interferon produced.
researchers found that the levels of interferon made while the lung cells were infected with the alpha variant were lower than all other covid-19 variants.
“we have never seen anything like this before; we know viruses adapt and we expect to see the proteins adapting so they work better in humans,” co-senior author greg towers said. but alpha is using its antagonism proteins, that help evade detection a little bit, and cranking up how much it makes. that is unique.”
towers says the real value of the discovery is its insight into how the virus evolved from the initial sars-cov-2 strain. it also helps researchers understand how protective innate immunity functions, he said.
during preliminary research, the scientists were able to identify some of the mutations found in alpha are also present in other variants of concern, such as delta and omicron. it is believed that they succeeded due to the mutations found in spike proteins.
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“it will be fascinating to see how the other variants, such as delta and omicron, perform comparatively in our lung epithelial systems,” co-author ann-kathrin reuschl said. “whether the viruses rely on similar approaches to innate antagonism or have evolved distinct strategies to evade the immune defences, will teach us not only about the viruses themselves but also about human biology.”
omicron has taken over delta as the dominant strain in the united states, according to cnn , with more than 73 per cent of new cases linked to the latest variant. the u.s. also broke its record for number of cases in a day this week, with 267,000, the new york times reports.
ctv reports that canada just passed the 2 million mark for covid cases since the start of the pandemic. and many provinces are reporting single day high case counts, including ontario (10,436), quebec (13,149), newfoundland (312), and nunavut (74) as of wednesday, according to cbc .
chris arnold is a toronto-based freelance writer.
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