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How powerful the “alpha” coronavirus variant has become

In December, British researchers discovered that: New variant It was sweeping their country. When arriving in other countries, the variant now known as Alpha tended to become more common in new homes. By April, it’s Dominant variants In the United States, that’s the way it is since then..

With Alpha’s rapid success, scientists are wondering how this variant conquered the world.Ah New research Point out one secret to success. Alpha negates the first line of immune defense in our body and gives more time for the mutant to grow.

“It’s very impressive,” said Dr. Maudley Laurent Roll, a physician and virologist at Yale University School of Medicine, who was not involved in this new study. “Successful viruses are the first. You have to go beyond the defense system. The more successful it is, the better the escape from the virus. “

The report was published online on Monday, but has not yet been published in a scientific journal.

Alpha has 23 mutations that set it apart from other coronaviruses. When this variant began to proliferate in the UK, researchers began looking into fine-tuning these genes and asked for an explanation as to why they spread faster than other variants.

Many researchers have focused on nine mutations that alter the so-called peplomer, which covers the coronavirus and allows it to enter the cell. One of these mutations is that the virus binds more strongly to the cell. It can help and increase the chances of a successful infection.

But other scientists are looking at how alpha affects the human immune response. Gregory Towers, a virologist at University College London, and his colleagues compared alpha-infected cells with cells infected with early variants of the coronavirus to propagate the coronavirus in human lung cells. ..

They found that lung cells containing alpha significantly reduced the production of interferon, a protein that switches on many immune defenses. They also found that in alpha cells, the defense normally switched by interferon. We found that the gene was quieter than cells infected with other variants.

For some reason, the most important alarm of the immune system was barely ringing in the presence of the alpha variant. “It makes ourselves less noticeable,” said Dr. Towers.

To investigate how Alpha achieved this invisibility, researchers looked at how the coronavirus replicates in infected cells. They found that alpha-infected cells make large amounts of an extra copy of a gene called Orf9b (about 80 times more than other versions of the virus).

“It’s off the mark,” said Nevan Crogan, a molecular biologist at the University of California, San Francisco, who co-authored the new study.

To Previous research, Dr. Krogan and his colleagues discovered that Orf9b produces a viral protein called Tom70 that locks a human protein. And it happens that Tom70 is essential for cells to release interferon when faced with an invading virus.

Putting all the evidence together, Dr. Krogan and his colleagues claim that the Alpha variant contains mutations that force the production of more Orf9b proteins. These proteins cluster in the human Tom70 protein, weakening interferon production and a complete immune response. Viruses that are protected from attacks are more likely to make a copy of themselves.

However, infected cells can gradually remove the Orf9b protein from the Tom70 molecule. Approximately 12 hours after infection, the alert system will begin to return online. And, thanks to the immune response, Dr. Towers said, “Everything is unleashed.”

Dr. Towers said that when the immune response is finally delayed, people infected with alpha respond more strongly than other variants, coughing and squeezing virus-laden mucus not only through the mouth but also through the nose. I guessed that it would be discharged. Diffusion is improved.

“What they are showing makes sense,” said Dr. Laurent Roll. But she wants to see more evidence in support of their conclusions. For example, scientists did not perform standard tests to measure the number of Orf9b proteins.

“That’s one of the things that can be of concern,” she said. Dr. Clogan said he and his colleagues are currently developing the test.

Dr. Clogan’s team has begun similar experiments on other variants, including the first variant identified in South Africa known as Beta and the first variant identified in India known as Delta. Preliminary results surprised them.

Both beta and delta push down interferon in infected cells. However, there are no signs of doing so by injecting large amounts of Orf9b protein into the cells. They may have developed their own tricks to manipulate our immune system.

“They all suppress the immune response in a variety of ways,” said Dr. Crogan.

Cecil Harmsworth, an immunologist at the Girvan Medical Institute in Sydney, Australia, said he was not involved in the study.

Current vaccines direct the immune system to recognize spelomers. However, studies of people who have recovered spontaneously from Covid-19 have shown that their immune system learns to recognize other viral proteins, including Orf9b.

Many researchers are incorporating a combination of coronavirus proteins into new vaccines. However, be aware that some proteins can actually reduce your immune system.

“This is a very tricky business, but the more you learn, the more you can do it,” said Dr. King.

How powerful the “alpha” coronavirus variant has become

Source link How powerful the “alpha” coronavirus variant has become

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