Common mutation in COVID-19 makes it more susceptible to vaccine, researchers say
Washington:
A common mutation in the new coronavirus that allowed it to spread rapidly around the world could also make it more susceptible to a vaccine, according to a study that proves some of the first concrete findings on how SARS-CoV-2, which causes COVID -19, evolves.
Researchers at the University of North Carolina at Chapel Hill and the University of Wisconsin-Madison in the United States noted that the new strain of coronavirus, called D614G, has emerged in Europe and has become the most prevalent in the world. .
Their study, published in the journal Science, shows that the D614G strain replicates faster and is more transmissible than the virus, which originated in China, which spread at the start of the pandemic.
While the D614G strain spreads faster, in animal studies it has not been associated with more severe disease, and the strain is slightly more susceptible to neutralization by antibody drugs, the researchers said.
“The D614G virus overtakes and surpasses the ancestral strain by approximately 10 times and replicates extremely efficiently in primary nasal epithelial cells, which are a potentially important site for person-to-person transmission,” said Ralph Baric, professor. at UNC- Chapel Hill.
Researchers believe that the coronavirus strain D614G dominates because it increases the ability of the spike protein to open cells for the virus to enter.
The D614G mutation causes a flap to open at the end of a peak, allowing the virus to infect cells more efficiently, but also creating a pathway to the virus’s vulnerable nucleus, the researchers said.
With an open shutter, it is easier for antibodies – like those in vaccines currently being tested – to infiltrate and deactivate the virus, they said.
“The original spike protein had a ‘D’ at this position, and it was replaced with a ‘G’,” said Yoshihiro Kawaoka, a virologist at the University of Wisconsin-Madison.
“Several articles had already described that this mutation makes the protein more functional and more efficient to enter cells,” said Yoshihiro Kawaoka.
This earlier work, however, relied on a pseudotyped virus that included the receptor binding protein but was not authentic, the researchers said.
Using reverse genetics, Ralph Baric’s team replicated a pair of mutant SARS-CoV-2 viruses encoding D or G at position 614 and compared the analysis of basic properties using cell lines, primary human respiratory cells; and mouse and hamster cells.
Researchers at the University of Wisconsin-Madison performed airborne replication and transmission studies with the original virus and the mutated version.
They found that the mutated virus not only replicated about 10 times faster, but also much more infectious.
The hamsters were inoculated with either virus. The next day, eight uninfected hamsters were placed in cages next to infected hamsters.
There was a separator between them so they couldn’t touch each other, but air could pass between the cages.
Researchers began looking for virus replication in uninfected animals on the second day. Both viruses were transmitted between animals by airborne transmission, but the timing was different.
With the mutant virus, researchers saw transmission to six out of eight hamsters in two days and to all hamsters by day four.
With the original virus, they saw no transmission on the second day, although all exposed animals were infected by the fourth day.
“We saw that the mutant virus transmits better in the air than the original virus, which may explain why this virus has dominated in humans,” said Yoshihiro Kawaoka.
The researchers also looked at the pathology of the two strains of coronavirus.
Once the hamsters were infected, they had essentially the same viral load and symptoms.
This suggests that while the mutant virus is much better at infecting hosts, it doesn’t cause significantly worse disease, they said.
However, the researchers warn that the results of the pathology may not be true in human studies.
(Except for the title, this story was not edited by GalacticGaming staff and is posted from a syndicated feed.)
