What’s new: Chinese researchers said in a paper published on Cell magazine that D614G, the genetic mutation of the spike protein, a dominant variant in the novel coronavirus, could make the virus 10 times more infectious than the original Wuhan-1 strain.
The study, published on July 17, performed by a team from the National Institutes for Food and Drug Control, found that certain mutations could make the virus more or less contagious and fatal. For example, as well as investigating mutations that could increase the virus’ infection rate the study also found the majority of deletions of glycosylation — a critical protein modification process, could make the virus less contagious, of which the ablation of both N331 and N343 drastically reduced infectivity, indicating the importance of glycosylation for viral replication.
In total, the researchers investigated 80 pseudotyped variants and 26 glycosylation site modifications in the spike protein for their infectivity and reactivity to neutralizing antibodies and sera from convalescent patients. Their results showed that 10 mutations that they investigated, such as N234Q, were markedly resistant to some neutralizing monoclonal antibodies, whereas six others, mostly glycan deletion mutants, caused the virus to become over four times more sensitive to one or two of the 10 tested sera.
The background: The close monitoring of the virus strains of Covid-19 currently in circulation is valuable to the research and development of vaccines and therapeutics because single-stranded RNA viruses like the novel coronavirus — which are known to have higher mutation rates — usually keep evolving over time in human populations.
According to the Chinese Center for Disease Control and Prevention (CDC), the D614G mutant strain is associated with the outbreak in Beijing’s Xinfadi wholesale market in June. The strain began to spread widely in Europe in February and later became a dominant strain across the globe. Researchers have previously found that the D614G mutation could lead to increasing infectivity and fatality rates of the virus.
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