COVID-19 breakthrough shows that the virus uses three different techniques to evade the immune system and increase its viral load in infected individuals
While COVID-19 vaccinations are becoming widely available and the number of cases in the United States continues to decrease, research into COVID-19 is still strong and yielding new insights. Continuing COVID-19 research is not only important for potentially addressing emerging variants and the threats they could pose but is also providing valuable scientific advances into how other infectious diseases affect the body.
A new breakthrough in COVID-19 research, published in Nature May 12, 2021, has provided new observations about how SARS-CoV-2 evades the immune system, causing a more severe infection than many other types of viruses. This study was conducted by researchers at the Weizmann Institute of Science in Rehovot, Israel, led by Noam Stern-Ginossar, PhD.
“Our research helps to explain why this virus causes such serious disease suddenly,” Stern-Ginossar, of the Weizmann Institute’s Molecular Genetics Department, said in a recent interview. “We have seen close up that it basically harms the ability of cells to send the necessary early signals to the immune system.”
Two New Virus Processes Discovered
The researchers found that, while SARS-CoV-2 affects the ability of cells to make proteins through a process that had already been discovered, it also causes two other important effects that enhance the virus’s ability to evade the immune system. This allows the virus to generate a more severe infection before it is detected by the body’s immune system.
The first of the two new processes that were discovered by Stern-Ginossar’s lab is that SARS-CoV-2, the virus that causes COVID-19, inhibits the transport of messenger RNA (mRNA) from being transported out of the cell nucleus to where it can be translated. This effectively cuts off communication between genes and the ability of the cells to read messages from the genes. The second additional process discovered was that SARS-CoV-2 causes mRNA to be quickly degraded, meaning that messages that do make it from the DNA to the cell will not be active for long.
“The first of these processes was known, but the others were not,” explained Stern-Ginossar. “We now understand on a molecular level why we’re not mounting efficient anti-viral response, and knowing this [we] may be able to better target therapeutics.”
SARS-CoV-2 Coronavirus Undetected Until a Certain Point
When these two new mechanisms are coupled with suppression of the ability of the cell to read the mRNA, the result is a profound effect on how the DNA in the cell communicates with the rest of the cell, greatly suppressing the ability of the cell to warn the immune system of infection. This allows the virus to infect the body undetected until a large amount of the virus is present, causing a more severe infection and more dangerous symptoms.
“This is why, with COVID-19, everything in terms of immune response can be badly postponed, and by the time the body feels SARS-CoV-2 there can be huge amounts of the virus,” Stern-Ginossar explained.
Implications of New COVID-19 Viral Load Research
There are several interesting implications from this research. The first is that these newly discovered mechanisms indicate that the viral load is an important datum that can indicate how severe an infection could be. The purpose of the virus’s actions seems to be to increase the viral load to the greatest extent possible prior to detection by the immune system.
There have been multiple studies into how the viral load and disease severity are connected, and viral load testing can be easily performed during a PCR test, potentially yielding valuable information. (See SARS-CoV-2 Viral Load in Patients Seems to Be Decreasing Over Time, New Research Shows and Viral Load Can Predict COVID-19 Severity Only in Saliva Specimens, New Study Shows.)
Another implication of this study is the fact that COVID-19 degrades mRNA. Two of the authorized COVID-19 vaccines use mRNA to create immunity, and this new finding could indicate that the vaccine may be less effective in people who have an active COVID-19 infection.
Ultimately, the greatest outcome of this study will likely be the therapeutic techniques that can be developed to target the new processes that have been discovered. A better understanding of how the virus works and causes its effects can lead to better treatments for COVID-19 and may have potential implications for the treatment of other infectious diseases in the future.
—By Caleb Williams, Editor, STAT Intelligence Briefings
Related Resources:
The Times of Israel: Why does COVID make people so sick, so quickly? Israeli geneticist has an answer
