A common mutation of the novel coronavirus that has allowed it to spread quickly around the world could also make it more susceptible to a vaccine. This emerges from a study showing some of the first concrete findings on how SARS-CoV-2 causes COVID -19 is evolving.
Researchers from the University of North Carolina at Chapel Hill and the University of Wisconsin-Madison in the United States found that the new coronavirus strain D614G has emerged in Europe and is the most common worldwide.
Their study, published in the journal Science, shows that the D614G strain replicates faster and is more transmissible than the Chinese-derived virus that spread at the beginning of the pandemic.
While the D614G strain spreads faster, it wasn’t associated with any more severe disease in animal studies, and the strain is slightly more sensitive to neutralization by antibody drugs, the researchers said.
“The D614G virus competes and grows approximately ten-fold beyond the ancestral line and replicates extremely efficiently in primary nasal epithelial cells, which are a potentially important site for human-to-human transmission,” said Ralph Baric, professor at UNC. Chapel hill.
Researchers believe that the D614G strain of coronavirus dominates because it increases the ability of the spike protein to open cells for the virus to enter.
The D614G mutation causes a flap at the top of a spike to open, which allows the virus to infect cells more efficiently, but also creates a route to the virus’ vulnerable core, the researchers said.
With an open mouth, it’s easier for antibodies – like those in the vaccines currently being tested – to infiltrate and deactivate the virus, they said.
“The original spike protein had a ‘D’ in that position and was replaced with a ‘G’,” said Yoshihiro Kawaoka, a virologist at the University of Wisconsin-Madison.
“Several publications have already described that this mutation makes the protein more functional and more efficient to get into cells,” said Yoshihiro Kawaoka.
However, that earlier work relied on a pseudotyped virus that contained the receptor binding protein but was not authentic, the researchers said.
Using reverse genetics, Ralph Baric’s team replicated a matching pair of mutant SARS-CoV-2 viruses encoding D or G at position 614 and compared the analysis of the basic characteristics using cell lines, primary human respiratory cells, and mouse and Hamster cells.
The University of Wisconsin-Madison researchers performed replication and transmission studies in the air with both the original virus and the mutated version.
They found that the mutated virus not only replicates about ten times faster, it is also much more contagious.
Hamsters have been vaccinated with one virus or another. The next day, eight uninfected hamsters were caged next to infected hamsters.
There was a partition between them so they couldn’t touch, but air could flow between the cages.
On the second day, the researchers began looking for replication of the virus in the uninfected animals. Both viruses were airborne between animals, but the timing was different.
With the mutated virus, the researchers saw transmission to six out of eight hamsters within two days and to all hamsters on the fourth day.
With the original virus they saw no transmission on the second day, although all exposed animals were infected on the fourth day.
“We saw the mutant virus airborne better than the original virus, which may explain why this virus dominates in humans,” said Yoshihiro Kawaoka.
The researchers also examined the pathology of the two coronavirus strains.
Once infected, hamsters exhibited essentially the same viral loads and symptoms.
This suggests that while the mutated virus infects hosts much better, it does not cause disease much worse, they said.
However, the researchers caution that the pathological findings in human studies may not be accurate.
(Except for the headline, this story was not edited by GossipMantri staff and posted from a syndicated feed.)